ISSN:0365-6217    

DOI:10.1039/AR96158FP001

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

ANNUAL REPORTSON THEPROGRESS OF CHEMISTRYGENERAL AND PHYSICAL CHEMISTRY1. INTRODUCTIONTHIS year we have selected a small number of topics in Physical Chemistryand reported on them in some detail. The policy is to attempt to cover thevarious aspects of the subject over a period of years, the choice of subjectsdepending on the rate a t which contributions to the subject are growing.Theoretical calculations on the properties of small molecules have notbeen reported for some time, so we include an account of this work and itsmost recent developments in a way which we hope will be of value to physicalchemists.Great advances in the study of molecular energy transfer processes arebeing made a t the present time, and the report on this subject covers rathercompletely the most recent work.The special shock-tube method of study-ing chemical reactions is reported, and recent advances described.I n recent years a great deal of spectroscopic work has been devoted tothe study of intermolecular interactions, so we include a report on studiesof solvent effects in infrared spectra.The relatively new subject of nuclear magnetic resonance has grown ina quite remarkable way and its applications to chemical problems havebeen extremely varied. The availability of commercial spectrometers hasresulted in a tremendous increase in the literature of this subject, so we haveattempted to summarise the present position as thoroughly as possible.R. E. R.2. WAVE-MECHANICAL CALCULATIONS ON ATOMS ANDSMALL MOLECULESALTHOUGH it is written for chemists without any specialized experience ofthe application of rigorous wave-mechanical techniques to the study ofatomic and molecular systems, this report deals exclusively with whatCoulson 1 has catalogued as “ Group I ” quantum chemistry.It describescalculations which do not have recourse to experimental data other thaninteratomic distances and general “ constants,’’ which are limited at presentto the accurate estimation of total electronic energies rather than excitation,ionization, or dissociation energies, and which, at their best, give wave1C. A. Coulson, Rev. Mod. Phys., 1960, 32, 1708 GENERAL -4ND PHYSICAL CHEMISTRYfunctions good enough to permit the reliable evaluation of physical proper-ties dependent on electronic-charge distribution.*An astonishing amount of work of this kind was carried out in the &stdecade of wave mechanics, with a degree of success that now seems almosthumiliating. The subject was then very largely abandoned during a, longperiod of preoccupation with the seemingly simple properties of n-electronsystems. In the past few years, however, the availability of automaticcomputers and increasing dissatisfaction with the often uninterpretableresults of ‘‘ Group I1 ” calculations have combined to restore “ Group I ”quantum chemistry to favour. Whether recent developments are to beregarded as progress in quantum chemistry or progress in numerical analysisis a matter of taste.This Report covers work published between 1959 and 1961, but by nomeans completely, and we have endeavoured to survey recent trends ratherthan recent publications.In general, we have omitted papers concernedsolely with computational techniques, papers describing manifestly unsuc-cessful calculations, and papers describing calculations without an obviousobjective. As the topic was reviewed last year,5 we have not consideredpublications dealing specifically with the electrical and magnetic propertiesof molecules.Because the Report is not intended for the specialist theoretician, thefirst three sections are purely expository. They are concerned mainly withexplaining the term ‘‘ self-consistent field,’’ which is used so indiscriminatelynowadays in molecular quantum chemistry as to be in danger of losing allsignificance. Although these sections are illustrated by reference to theground state of the beryllium atom, the analysis is applicable, mutatismutandis, to other atoms and to molecules.A considerable proportion of the remainder of the Report is devoted towork on atoms, especially small atoms; this is a fair reflexion of currentdevelopments.Apart from their intrinsic chemical interest, calculations onatomic systems are invaluable as models for calculations on molecularsystems.Determinantal Wave Functions.-Except in a small number of highlyspecialized calculations, the wave function, Y, for a single configuration ofan N-electron atomic or molecular system is taken to be a product of N one-electron wave functions (spin-orbitals ?),suitably antisymmetrized in accordance with the general form of Pauli’s*P.-0.Lowdin, Adv. Chem. Phys., 1959, 2, 207.sP.-O. Lowdin, Ann. Rev. Phys. Chem., 1960, 11, 107.4T. Fueno, Ann. Rev. Php. Chern., 1961, 12, 303.‘A. D. Buckingham, Ann. Reports, 1960, 57, 53.* Much more sophisticated accounts of recent developments in ‘‘ Group I ” quantumchemistry have been given by Lowdin; as 3 and “ Group I1 ” quantum chemistry(semi-empirical and semi-quantitative work on large molecules) has been reviewed byFuen0.4 t A spin-orbital is a function of the spatial co-ordinates of a single electron multipliedby one of the two possible spin factors, a or IsSTEWART : WAVE-MECHANICAL CALCULATIONS 9principle.s If N is even and the spin-orbitals comprise N / 2 spatially dis-tinct orbitals having the spin factor a (m, = 6) plus the same N / 2 orbitalswith the spin factor B (ms = -+), the antisymmetrized wave function issimply the Slater 7 determinant *' YlW Yl(2) * Yl")' YN(1) YN(2) - - Y"N>y = ~ Y2W Y2(2) ' - yl2(N) .. . . . . . . . . . .= det{ Yl(l)Y2(2) ' Y N ( W (2)A single Slater determinant suflices also if all the spin-orbitals which do notoccur in spatially identical pairs in the configuration considered have thesame spin factor (all m, = Q or all m, = -8) ; but in general %I linear com-bination of Slater determinants is required. Thus for the ground state andthe lowest excited states of beryllium we write, adopting the abbreviatednotation (2), and using bars to distinguish spin-orbitals with ms = -4 fromthose with ms = Q,W1s22s2 l8) = det(Yls(l)yls(2>Y2,(3)~2,(4) I ; (3)Y/(1S22S2P lp) = det {Yls(l)yls(~>Y2s(3)y2,(4) 1 - det {Yls(l)yls(2>~2,(3)Y2,(4) I ;WS22S2P 3p) = det {YlS(l>YlS(2>Y2,(3)~2~(4) I + det {Yls(l)y1,(2>~2s(3)Y2,(4) 1or det{Y,,s(1)~,(2)ly2,(3)Y2,(4) 1or det {Yls(l>~ls(2)y2s(3)y2~(4) 1.(4)If any of the N spin-orbitals selected for the product wave function ( 1 ) aredegenerate with others not included, the arbitrary selection will not nor-mally provide a satisfactory wave function: all possibilities must be con-sidered; function ( 1 ) must often be replaced by a linear combination of pro-ducts; and the determinantal form of the wave function must be extendedcorrespondingly.This situation occurs notably in atoms with incompleteshells, and in the excited states of symmetrical molecules. For example,y(ls22P2 '8) = det ~Y1,(1)yls(2)Y,(3)y)2(4) 1 + det(yls(l)~l,(z)ly,(3)y,(4) 1- det(Yi,(l)yli,(2)Y,(3)y,(4) 1, (5)where x = 2px, y = 2py, x = 2pz.Superposition of collfigurations (configuration ' I interaction ") causesa further increase in complexity. Even where degeneracy has not to betaken into account, it is seldom sufficient in work of high accuracy to buildup an N-electron wave function from N spin-orbitals. A larger set mustbe considered, and a linear combination formed from products of functionsrepresenting various ways of choosing N members of the set :Y = C&+ C2Y2 + C3Y/3 + . . . (6)C. A. Coulson, " Valence," Oxford University Press,,,2nd Ed., 1961.J.C. Slater, " Quantum Theory of Atomic Structure, McGraw-Hill, New York,* Except where their inclusion serves a useful purpose, normalizing factors areetc., 1960, (a) Vol. I; ( b ) Vol. 11.omit,ted from all wave functions quoted in this Report10 GENERAL AND PHYSICAL CHEMISTRYThe coefficients of the linear combination (6) are determined by the applica-tion of the variation principle; those of linear combinations of the types (4)and (5) are obtained by the use of angular momentum operators.7bSelf-consistent-field Wave Functions.-If the optimum forms of all theorbitals yl,y2, . . . , yN, comprising a single configuration are determined(to within arbitrarily specified limits) by a completely Jexible application ofthe variation principle, the orbitals are known as Hartree-Fock orbitals or(for reasons which are now mainly historical) as self-consistent-field orbitals.The total energy obtained in this way is usually found to be 98-5-99*5%of the observed energy.The term correlation energy is applied to the difference between theHartree-Fock energy of an atomic or molecular system and the energy cor-responding to an exact solution of the Schrodinger equation for the samesystem.[Because of quantum-electrodynamic and relativistic effects, 8which increase rapidly with increasing atomic number, the exact eigenvaluemay not be precisely the same as the observed energy.]There are two ways of determining the best possible forms of the orbitalsyl, y2, .. . , yN. We illustrate them by considering the ground state of theberyllium atom, ls22s2 18. This is a particularly simple system, for there areno incomplete electron shells, and the orbitals are spherically symmetrical;but, where nothing to the contrary is indicated, the results derived for theparticular case of beryllium can safely be generalized.The energy corresponding to the four-electron wave function (3) isE = J YHYdr/J Y2dT [dr = d ~ , d ~ ~ d ~ , d ~ , ] (7)and this is broken down by standard techniques (Slater 7a) into integralsinvolving one-electron wave functions :Jdet (y& )qww2s(3)q2s(4) )H def (~ls(l)qls(2)Y2s(3)W2s(4) Id?Jdet (YlS( 1$ls(2)w2s(3)q2s(4) 1 det (Yls(l)~1,(2)w2s(3)q2s(4) )drs CYlS(1 )~lS(2)W2s(3)q2s(4)1 det ( Y l S ( 1 )q1s(2)Y2s(3)V28(4) IdT= f [Yls(l)qls(2)W2s(3)q2s(4)IH def (Yls(l)qls(2)V2s(3)Y2s(4) w= s ~ ~ Y l S ~ ~ ~ ~ l S ~ ~ ~ Y 2 S ~ ~ ~ - [YlS(l )W2,(2>Wzs(3>qls(4)1+ CY 2s ( 1 )V2s (2)Y IS( 3 )VlS(4) 1 )dTE =- s [Yls(~)~1s(2)w2s(3)~2s(4)lH det (YlS(1 )qls(2)Y2s(3)~2s(4 w-(8)In Hartree atomic units(9)4 1 1 1 1 1 1H = 5 (-a.: - <) + g + < + < + + + G'i=lEqn.(9) is substituted in (8), and the variation principle is then appliedto determine the optimum forms of yls and y2s.If, for computational convenience, we segregate from E all the integrals8A. Froman, Rev. Mod. Phys., 1960, 32, 317.OH. Shull an4 G. G. Hall, Nature, 1959, 184, 1559STEWART : WAVE-MECHANICAL CALCULATIONS 11in which yls appears, calling their sum El,, and do likewise for the otherthree spin-orbitals, we find, if yIs and y2s are orthonormal,yls( l ) y ~ 2 ~ ) ~ l s ( l)dz1dt29-12+ 1y2,( 1)y2“2)~2~)y2s( l)dz1dz2r12+ 2Jyas( l)y1s(2)y1s(2)y2s( 1)dz1dz2r12In (10) and (1 1) we have reduced the set of numerals identifying the electronco-ordinates from four to two, and we have omitted the spin factors, whichgive unity on “integration.”The minimum value of El, (or E2s) clearly represents the kinetic energyof one of the Is (or 2s) electrons plus its potential energy in the field of thenucleus and the other three electrons.To find the optimum form of, say, yl, it is immaterial whether we mini-mize E or El, with respect to variations in yls.There is, however, animportant difference between the minimum energies obtained : whereas Ecorresponds to a measurable quantity (the sum of the four ionization ener-gies), the “ one-electron ” energy El, is a purely artificial quantity.More-over,for each of the electron-repulsion integrals included in E is counted twice onthe left-hand side of the expression (12).Of the two methods for determining the optimum forms of yls and y2sone is of recent developrnent,l0 while the other dates from the early yearsof quantum chemistry.1lRoothn’s method. 12-14 that for atoms of lowatomic number (where comparison with spectroscopic results is possible)remarkably accurate estimates of the total electronic energy (to within 1%)can be obtained from wave functions built up from orbitals of exceedinglyloC. C.J. Roothaan, Rev. Mod. Php., (a) 1951, 23, 69; ( b ) 1960, 32, 179.l1 D. R. Hartree, “ The Calculation of Atomic Structures,” Wiley, New York, 1957.la W. E. Duncanson and C. A. Coulson, Nature, 1949, 164, 1003.C. C. J. Roothaan, Technical Report, Laboratory of Molecular Structure and14R. G. Breene, Phys. Rev., 1958, 111, 1111; 1959, 113, 809; 1960, 119, 1615El, + 4 s + E2, + E 2 , > E, (12)It is well knownSpectra, University of Chicago, 1955, p. 2412 GENERAL AND PHYSICAL CHEMISTRYsimple form. In the case of beryllium ls22s2 W, if the two orbitals aretaken to bey1s = exp(--r),y2s = r exp( -br) + A exp( -cr), (13)where a, b, and c are variational parameters, and A is adjusted to ensureorthogonality between yls and y2s, the calculated 12 energy is -14-552 H.*The observed energy, corrected l5 for experimental error, is -14,66745 H.When functions as simple as (13) give accurate results, it is reasonableto expect that the best possible forms of yls and yyZs might be obtained byvariation of the linear parameters C in a finite expansion(14)with n fairly small and the " basis functions " x of the same form as the right-hand terms in function (13).This expectation has been realized not onlyfor light atoms but (see below) for atoms with electronic configurations upto 417. For beryllium itself Roothaan, Sachs, and Weiss l6 have used thebasis functionsY = ClX1+ (72x2 + * ' + cnxn,x1 = exp(-6*50r), x3 = exp(-3*40r), x5 = exp(-O-90r),x2 = r exp(-6-50r), xa = r exp(-3.40r), x6 = r exp(-O40r). (15)They obtained an energy of -14.57298 H, and showed this to be the bestenergy attainable (within the limits of precision implied) from a wavefunction of the form (14).It is customary in self-consistent-field calculations of this type to use thesame basis functions for all orbitals of a given symmetry (s, p , d, .. .). Thesuccessive quantum levels (e.g., Is, 2438, . . .) corresponding to different setsof coefficients in function (14) are then obtained by the solution of a secularequation (much as when molecular orbitals are expanded as linear combina-t,ions of atomic orbitals 6 ) . Roothaan lo has developed general matrixmethods for evaluating the coefficients (i.e., the orbitals) and the energies.It can be shown 79 11 that,provided the variations are completely flexible and not limited to a fewarbitrarily chosen parameters, the orbitals which minimize the energies (10)and (11) are the same as those which satisfy the Hartree-Fock equationsHartree-Pock method (numerical integration).- _ - - ~~ ____ ___ ___ _____ ___ - -I5R.E. Watson, Phys. Rev., 1960, 119, 170.l6 C. C. J. Roothaan, L. M. Sachs, and A. W. Weiss, Rev. Mod. Phys., 1960,32,186.recommendations in part, we use the symbolsH (= Hartree) and B (= Bohr) in this report for the " reduced " atomic units of energyand length.*Following Shull and Hall'sFor infinite nuclear mass 1 H = 27.210 ev, and 1 B = 0.52097 ASTEWART : WAVE-MECHANICAL CALCULATIONS 13If yls and yps are normalized, equation (10) can be obtained from (16) bypremultiplying the latter by vlS( 1) throughout and integrating over theco-ordinates of electron 1; likewise (11) can be obtained from (17).[Dummynumerals, 1 and 2, are used in (16) and (17) as in (10) and (ll).]The solutions to simultaneous integro-differential equations of the type(16) and (17) are obtained by numerical integration, and are usually pre-sented in the form of a table of values of Pls(r) and P2,(r) as functions of r ,whereP(r) = rR(r),R(r) = 2 d y (for s orbitals). (18)The symbol R (superfluous for s orbitals) is used to represent the radialfactor in orbitals ( p , d, f, . . .) having angular dependence. For s orbitalsR differs from y only because R is normalized in the sense(19)P(r) is the square root of the function 4nr2y2 which measures the prob-ability of finding an electron on the surface of a sphere of radius r (Coulson 6).In principle, solution of the Hartree-Fock equations yields an infinitenumber of orbitals (Is, 2s,3s, .. . in the present case), whereas the numberof orbitals available from a h i t e set of basis functions (as in Roothaan’smethod) is determined by the size of the set. In practice this is not amatter of consequence, except that it is not easy to choose a severely trun-cated basis set which adequately represents wave functions of widelydiffering principal quantum number.For nearly thirty years the numerical integration of the Hartree-Fockequations was the only practicable method of determining the optimumforms of atomic orbitals.Because of lack of precision, it was never anentirely satisfactory method, and it had the disadvantage of yielding atomicwave functions in a form in which they could not be used directly in non-spherical systems (Le., in molecular calculations). In the past two yearsit has been displaced almost completely by developments of Roothaan’smore straightforward procedure. A very recent report, however, suggeststhat the problems of precise numerical integration may have been over-come.17The simple energy expressions given in equations (10) and (11) areobtained only if the 1s and 2s orbitals are orthonormal. That they areorthogonal is readily demonstrated if function (16) is pre-multiplied byy2,(l) throughout, and (17) by ylS(l), integration then carried out over theco-ordinates of electron 1, and the second equation subtracted from thefirst. This gives(20)El, and E,, are not equal; therefore J’ yls(l)y2s(l)drl = 0.Orthogonality isalways ensured automaticdly in systems consisting only of “ doubly occu-pied ” orbitals; in other cases additional terms involving all the orbitals ofthe same symmetry appear on the right-hand sides of the Hartree-Fockequations.J R2r2dr = S P2dr = 1.0 = (El3 - E2S) s Yls(l)Y2s(l)d~l-l7 (a) D. F. Mayers, ( b ) D. A. Goodings, unpublished work quoted in ref. 18.leR. E. Watson and A. J. Freeman, Phys. Rev., 1961, 124, 111714 GENERAL AND PHYSICAL CHEMISTRYIn self-consistent-field calculations involving orbitals with angulardependence ( p , a, f, .. .) the assumption is always made, explicitly orimplicitly, that y = R(r)@(O)@(+), where R(r) is a function of R only, andthe angular factors (spherical harmonics) are the same as for the hydrogenatom (this is indeed true for S states). The problem of determining theoptimum forms of the orbitals y then reduces to that of determining theoptimum forms of functions of r only; the Hartree-Pock equations areusually written in terms of the variable P = rR.Ionimtion energies. Though one-electron energies (e.g., El, and E,, inthe case of beryllium) are artificial quantities defined for computational con-venience, they are puzzlingly closely related to the corresponding observedionization energies. It is easy to show (Koopmans’s theorem 19) that themerence between the self-consistent-field energy for beryllium 1s22s2and that for beryllium 1822s 2 5 is given by expression (lo), provided that ylSand y2s are taken to be the same for the cation as for the neutral atom.Butthis they are not.Ionization energies are obtained in two ways in Hartree-Fock calcula-tions : either the self-consistent-field energies are calculated separately forthe neutral atom and the ion, or otherwise the ionization energy of theneutral atom is taken to be simply the absolute value of the one-electronenergy concerned. Oddly enough, whereas the strict calculation usuallygives poor results, the rough calculation based on Koopmans’s theorem oftengives astonishingly accurate results.It is easy to account for the failure ofthe strict calculation (an ionization energy being calculated as the differ-ence between two very large quantities, each slightly in error), but not forthe success of the rough one.Correlation Energy.-However satisfactorily the forms of the indi-vidual orbitals are determined, a self-consistent-field wave function cannever be an exact solution of the Schrodinger equation for a many-electronsystem. The difference between the Hartree-Fock energy and the energycorresponding to an exact solution is known as the correlation energy, andis usually accounted for as follows. Although the density distribution ofany electron in a system described by a Hartree-Fock wave function neces-sarily depends on the density distributions of all the other electrons, theHartreeFock wave function cannot provide for the “ instantaneous ”repulsive effect of the various electrons on each others’ positions, and itthus tends to overestimate the electron-repulsion energy.The discrepancy caused by the lack of proper correlation of the individualelectronic motions is a relatively small one (usually 0.5-1*5% of the totalelectronic energy), but it is much larger than many energy differences ofchemical interest (e.g., transition, ionization, and dissociation energies), and,moreover, there are many purposes for which a Hartree-Fock wave func-tion is not usually suiliciently accurate (e.g., the calculation of oscillatorstrengths and various quantities involving coupling between the electronsand the nucleus).Now that the self-consistent-field wave functions canbe obtained quite straightforwardly, a great deal of attention is being devotedto the production of really accurate wave functions. Even in systems ofIsT. A. Koopmans, Physica, 1933, 1, 104STEWART WAVE-MECHANICAL CALCULATIONS 15only a few electrons this is a very diflicult problem, despite the constantextension of computing resources. Four procedures for obtaining improvedwave functions are in regular use for molecular as well as atomic systems.The attempt to base a many-electron wave function on an antisymmetrized product of one-electronwave functions can be abandoned altogether, and the many-electron wavefunction expanded instead as a power series in the co-ordinates and relativeco-ordinates of the various electrons.Completely successful applicationsof this technique to the helium atom 2 * ~ 21 and the hydrogen molecule 22 aredescribed below, but the method is not of general application.Because single determinants lead to moretractable numerical analysis than linear combinations of determinants, ithas been customary in self-consistent-field calculations to use the minimumnumber of radial functions consistent with Pauli’s exclusion principle, onefor each shell (Is 2s, 2p, . . .) in the case of atomic systems. If this restric-tion is relaxed, and “ closed ” shells are replaced by “ open ” shells (e.g.,if four orbitals instead of two are used for beryllium ls22s2 W), the calculatedenergy is improved considerably, at least in the case of Is electrons.The only general method of obtainingespecially accurate wave functions which at present offers the promise ofextension to large atoms and molecules is that of “superposition of con-figurations,” also known as < < configuration interaction.” If Yl representsone way of selecting N orbitals from a larger set to make up an N-electronwave function, and Y2, Y3, .. . , YN represent other ways, then the varia-tion principle ensures that the linear combination (6) is a better wave func-tion than any of Yl, Y2, . . . , YN taken separately. Fully automatic com-puting programmes are available for calculations of this type on atomic andmolecular systems (Boys and Cook 23); but the problem of selecting sets ofone-electron functions which give accuracy without unwieldiness has notyet been solved.The most obvious way of improving a“ non-correlated ” wave function is to multiply it by a correlation function, x, which ensures a reduction in amplitude as any of the interelectronic dis-tances decreases.For two-electron systems 249 25 the simplest correlationfunctions which have been used successfully arewhere a, #?, y, 6 are variational parameters.The four methods of obtaining wave functions more satisfactory thanthose resulting from Hartree-Pock calculations are discussed below in rela-tion to specific atoms and molecules. It is interesting to note that thesemethods were all introduced by Hylleraas more than thirty years ago.26(a) Wave functions without an orbital basis.(b) Open-shell wave functions.(c) Superposition of conjiguratiom.(d) Correlated wave functions.x = exp(a9i2), x = 1 + pr12, x = 1 - y exp(-67i,), (21)zoT. Kinoshita, Phys.Rev., 1957, 105, 1490; 1959, 115, 366.21C. L. Pekeris, Phys. Rev., 1958, 112, 1649; 1959, 115, 1216.22 W. Kolos and C. C. J. Roothaan, Rev. Mod. Phys., 1960, 32, 219.23S. F. Boys and G. B. Cook, Rev. Mod. Phys., 1960, 32, 285.24 C. C. J. Roothaan and A. W. Weiss, Rev. Mod. Phys., 1960, 32, 194.45 W. Kolos and C. C. J. Roothaan, Rev. Mod. Phys., 1960, 32, 205.zsE. A. Hylleraas, 2. Physik, 1928, 48, 469; 1929, 54, 347; E. A. Hylleraas andB. Undheim, ibid., 1930, 65, 75916 GENERAL AND PHYSICAL CHEMISTRYA comprehensive review of the correlation problem in quantum chemistryhas been given by L o ~ d i n , ~ and Slater 7b has provided a valuable intro-duction to the subject.Helium Atom.-As in the earliest years of quantum chemistry, thehelium atom and its isoelectronic ions (1 < 2 < 10) have recently beenstudied far more intensively than any other atomic or molecular system.As a guide to the effectiveness of the miscellany of calculations which comewithin the scope of this report, we list in Table 1 the energies correspondingto wave functions of five clearly defined types.TABLE 1.Wace functions for the ground state of heliumWave functionexp(-ccr, - cr2)exp(-ccr, - c’rr,) + exp(-c’r, - w2)[C = 2.1832; C’ = 1.18851$(l)$(2) [SCF: optimum $1Exact[c = 1.68751+(1)$’(2) + $’(1)$(2)[optimum $ and $’I* J.N. Silvennan, 0. Platas, and F. A. t Ref. 16.$ C. C. J. Roothaan and A. W. Weiss,TRef. 20 and 21.% % of.Energy (H) of exact correlationenergy energyincluded- 2.84766 98.069-2.87566 * 99.034 33.25-2.86168 t 98.552 0.00-2.87798 $ 99-1 14 38.77Mat,sen, J. Chem. Phys., 1960, 32, 1402.-2.90372 7 100.000 100~00Rev. Mod. Phys., 1960, 32, 194.The exact value quoted in Table 1 was obtained from calculations ofastonishing precision carried out independently by ICinoshita 20 andPekeris,Z1 both abandoning all attempt a t orbital formulations of the wavefunction. Kinoshita adopted an 80-term expansion,in Hylleraas’s 26 co-ordinatess = rl + r2, t = rl - r2, u = r12, (23)using the variation principle to evaluate the coefficients Clms.The exponentsI , m, 12 were positive integers * (n even) not greater than 10, used in 80 dis-tinct combinations.Aiming at even higher precision than Kinoshita, Pekeris used a 1078-term wave function in James and Coolidge’s z8 “ perimetric ” co-ordinates,determining the coefficients by solving the wave equation. He calculatedthe electronic energy to be -2.903724375 H.The purpose of these extraordinarily elaborate computations was in partt,o match the accuracy of Herzberg’s 29 determination of the ionizationenergy of helium: in this they were completely successful (Table 2).Kinoshita obtained an energy of -2.9037237 H.27 H. M. Schwartz, Phys. Rev., 1960, 120, 483.28 H. M. James and A. S.Coolidge, Phys. Rev., 1937, 51, 857.29 G. Herzberg, Proc. Roy. SOC., 1968, A, 248, 328.* Schwartz 27 showed subsequently that the convergence of Kinoshita’s wave func-tion might be improved by the use of half-integral exponents for 9 and uSTEWART : WAVE-MECHANICAL CALCULATIONS 17TABLE 2. Calculated ionizution energy of helium (cm.-l)Kinoshitrt PekerisNon-relativistic ionization energy 198317.45 & 0-11 198317.3747Mass-polarization correction -4.786 f 0.006 -4.7854Relativistic correction -0.557 f 0.09 -0.5636Electrodynamic correction (Lamb shift) -1.336 f 0.2 -1.339 & 0.2Corrected ionization energy 198310.17 198310.687Observed ionization energy 198310.82 & 0.15Notably successful calculations on the lowest triplet states of heliumhave been carried out by Pekeris 21 and by Traub and F01ey;~O they havegiven values for the s-electron density at the nucleus in excellent agreementwith those obtained from the hyperfine splitting.The Hartree-Fock energy quoted in Table 1 is one of a comprehensivecollection determined by Roothaan's l6 method for the 182, 1s?%, andls22s2 configurations of atoms and ions with 2 ranging from 2 to 10.Com-parison with the neighbouring results in the Table serves as a reminder thatthe label " self-consistent-field " implies a satisfactory and predictablestandard of accuracy rather than a very high one.Open-shell wave functions. A straightforward way of providing for somemeasure of electron correlation in ls2 configurations is to assign differentorbitals (y, y') to the two 1s electrons, writing the " open-shell" wavefunction asy = Y(W'(2) + Y'(UY(2) (24)Even with the simplest orbital forms 31 [ y = exp( -cr), y' = exp(-c'r)],this gives an energy superior to the Hartree-Fock energy (Table 1).In amore sophisticated treatment the optimum forms of the two orbitals can berepresented as different linear combinations of a small set of basis func-t i o n ~ . ~ ~ , 32 The majority of calculations aiming at high accuracy nowadaysuse open-shell wave functions.For excited states of helium such as lsns (n > 1) any orbital-productwave function is necessarily an open-shell wave function, and provision forelectron correlation is not a formidable problem. Ritter and Pauncz 33have obtained excellent results for n = 2 , 3 , 4 in the series from He toC4+ by using the simple wave function= 'v)lS(1)y'7ZS(2) + $%S(1)~1S(2)J (25)with ylS = exp( -w), and yns a four-term expansion in Epstein 34 functions(see below).As would be expected, the error in Ritter and Pauncz's resultsdecreased with increasing separation of the two electrons (0.0029 H forz = 2, n = 2; 0.0004~ for '2 = 2, n = 4).30 J. Traub and H. M. Foley, Phys. Rev., 1959, 116, 914.31 J. N. Silverman, 0. Platas, and F. A. Matsen, J . Chem. Phys., 1960, 32, 1402;C. W. Scherr and J. N. Silverman, ibid., p. 1407; M. Machacek and C. W. Scherr,ibid., 1960, 33, 242.32C. Franconi and J. A. Petruska, Bicerca, 1960, 30, 2152.33Z. Ritter and R. Pauncz, J . Chem. Phys., 1960, 32, 1820.34 P.S. Epstein, Phys. Rev., 1926, 28, 695; L. Pauling and E. B. Wilson, " Int,ro-duction to Quantum Mechanics," McGraw-Hill, New York, 1935, Q 27a18 GENERAL AND PHYSICAL CHEMISTRYSuperposition of configurations. A single-configuration wave functionof the formYI = Yl(l)Yl(2) Or YI = Yl(l)ly1’(2) + Yl’(l)Y1(2) (26)can be regarded as the first member of an infinite serieswhich will constitute an exact solution to the Schrodinger equation pro-vided the basis functions y form a ‘‘ complete ” set, i.e., a set such that anarbitrary function can be expanded as a linear combination of members ofthe set to within any specified limits of precision. By commencing with asingle configuration Yl and gradually superposing others it is possible toapproach nearer and nearer to an exact solution. But unless the basisfunctions y are carefully chosen, the convergence may be unworkably slow.Hydrogen-like basis functions (Is, 2s,2p, .. .) have been used extensivelyin the past in atomic and molecular calculations, but it is clear that they arenot satisfactory.2J 3 5 ~ 36 This is partly because they are incomplete unlessthe continuum is included, and partly because they increase so rapidly in“ size ” as the principal quantum number increases that the higher memberscan contribute but little to the representation of a function closely resemblinga lower member. The rapid increase in the size of hydrogen-like wave func-tions is due to the radial exponential factor, and is avoided by the simplereplacement of exp( - Zr/n) by exp( - Zr) ; this gives a complete set withouta continuum.The members of the set can conveniently be made ortho-gonal by increasing the order of the associated Laguerre polynomial factorsfrom (21 + 1) to (21 + 2 ) , in which case they are now often known asEpstein 3* functions. These functions were introduced into contemporaryquantum chemistry by Shull and Lowdin;37 they have been used successfullyeven in severely truncated sets.Shull and Lowdin 35 have used the lower members of a set of Epsteinfunctions for a thorough investigation of the effects of superposition of con-figurations in the ground state of helium. Including all 21 codgurationsbuilt up from the first six Epstein s functions, they obtained an energy of-2.87897 H, and improved this by about 0-023 H by the addition of p, d,and f functions.The behaviour of the scale parameter c in Shull and Lowdin’s 35 calcula-tions provides a useful illustration of the danger of endowing mere mathe-matical symbols with physical significance.The scale factor is well knownto have the value 1.6875 in the simplest wave function for helium,exp(-cr, - cr2); and the fact that this is leis than the value appropriateto the ion He+ (c = 2 = 2) is often attributed to the “ screening ” of oneelectron by the other. There is no wave-mechanical foundation for a beliefin screening, and it is noteworthy that Shull and Lowdin found c to increaseS5H. Shull and P.-0. Lowdin, J. Chem. Phys., 1959, 30, 617.36H. 0. Pritchard and F.H. Sumner, J . Phys. Chem., 1961, 65, 641.37 H. Shull and P.-0. Lowdin, J . Chem. Phys., 1955, 23, 1362; P.-0. Lowdin, ref.2 and 3STEWART : WAVE-MECHANICAL CALCULATIONS 19from 1.6875 to 2-37 as the number of configurations in their wave functionincreased from 1 to 21.Weiss 39 has applied an extended open-shell version of Shull and Lowdin’scomputations to the ls2 lX and the ls2s 3 5 states of helium and the iso-electronic cations (2 < 2 < 8). He reduced the calculated ground-stateenergy of helium to --2.90320~, and estimated the energy of the tripletstate (in which the correlation problem is not serious) with an error of only0.00002 H.Effective configuration-interaction calculations having simplicity ratherthan high precision as their object have been reported by Silverman, Platas,and Mat~en.~l They obtained an energy of -2.89523 H, using a two-termwave function of type (27), the first term being the same as the secondfunction in Table 1, the second term being built up from 2p orbitals.(See also Howell and Shu1L3*)Correlated wawe functions.Using helium wave functions of the formwithi = O i = O j = ORoothaan and Weiss 24 have made a detailed study of the effect of “ expan-sion length ” on the accuracy of calculated energies. With rn = n = 4they obtained an energy of -2.90319 H (y + y‘), and they concluded thatno improvement would result from the use of higher values of rn and n.[With rn = n = 0 Roothaan and Weiss’s function is, of course, the same asthe first function in Table 1.3Lowdin and Rhdei 40 have combined superposition of codgurations andthe correlation-factor method in one and the same wave fmction,where Yi is the same as in function (27).Building up their superposed con-figurations from Is, 28, and 3s orbitals only, they calculated the ground-stateenergies of the series H- to Be++ with errors of only 0.001--0.002 H.Wave functions of an altogether different type involving rI2 co-ordinateshave been used by Walsh and Borowitz 41 and by Hameka 42 in an exam-ination of Pluvinage’s 43 perturbation method (in which the Hamiltonianoperator is rearranged so that the perturbation term is not l/r12). In rela-tion to the computation required, the results are not especially encouragingfor either the ground state or the lower excited states.A number of papers on helium have appeared recentlywhich do not fall into any of the categories we have chosen for discussion.Amongst them are papers by Dalgarno 44 (expansion of correlation energy in38K.M. Howell and H. Shull, J . Chem. Phys., 1959, 30, 627.39 A. W. Weiss, Phys. Rev., 1961, 122, 1826.40 P.-0. Lowdin and L. RGdei, Phys. Rev., 1959, 114, 752.r l P . Walsh and S. Borowite, Phys. Rev., 1959, 115, 1206; 1960, 119, 1274.42 H. F. Hameka, J. Chem. Phys., 1961, 34, 884.43P. Pluvinage, Ann. Physique, 1950, 5, 145.44 A. Dalgarno, Proc. Phys. SOC., 1960, 75, 439; M. Cohen and A. Dalgarno, ibid.,Miscelkaneous.1961, 77, 16520 GENERAL AND PHYSICAL CHEMISTRYpowers of l/Z), Dalgarno and Stewart 45 (relativistic and radiative correc-tions), Hall 46 (scale factor varying with r), Scherr 47 and Gray and White-head 48 (second-order perturbation theory), Henderson and Scherr 49 (wavefunctions in momentum space).Interelectronic distance.As the short comings of single- configurationclosed-shell wave functions without correlation factors have long been associ-ated with their failure to provide for adequate separation of the two elec-trons, it is surprising how little work has been done on the relation betweenthe calculated interelectronic distance and the character of the wave func-tion. This need has now been met by Coulson and Neil~on,~* who have notonly determined the mean values of rI2 and l/rl2 for various wave functions,but also evaluated the probability distribution function for r12.Theirresults support current views in a most interestkg way, and they are quotedin Table 3 along witch results obtained by Pekeris.21TABLE 3. Electron correlation in the ground state of heliumWave functionexp( -crl - cr2) - 2.84766 1.296 1-055 1.0Self-consistent -field -2.86168 1.311 1-026 1.0exp(-cr, - c'r2).+ exp(-c'r, - cr2) -2.87566 1.394 0.993 1.0Six-term expansion m s, t, u - 2.9032 1.420 0.946 1.1Exact (Pekeris 21) -2.90372 1.422 0.946Criteria for msessing accuracy. Although almost all the energies quotedin this section have been obtained by the application of the variation prin-ciple, a most welcome feature of current work is the interest shown in othercriteria for assessing the qualities of wave functions (Lowdin 2, 3, 61).It isnow customary in calculations of high precision to study the effect of varia-tions in parameters and in expansion length, not only on the calculatedenergy, but also on the mean values of a variety of simple functions of theco-ordinates. This provides a check on internal consistency, and permitscomprehensive comparisons between wave functions of different degrees ofaccuracy. The availability of exact wave functions 2% 2 1 has proved mostvaluable in this respect.Various attempts have been made in recent years to extend the scope ofthe variation principle by using it to calculate lower energy bounds as wellas the usual upper energy bounds; they have not been very successful.52Lithium and Beryllium Atoms.-The most striking feature of recentwork on small atoms is the marked loss of accuracy as the number of elec-trons increases first from 2 to 3, and then from 3 to 4 (Table 4; cf.Table 1).Whereas self-consistent-field calculations almost always give, in theirreliable way, the same relative error irrespective of the number of electrons,45A. Dalgarno and A. L. Stewart, Proc. Phys. SOC., 1960, 75, 441.46 G. G. Hall, Proc. Phys. SOC., 1960, 75, 575.48B. F. Gray and R. Whitehead, J . Chem. Phys., 1961, 34, 1243.40M. G. Henderson and C. W. Scherr, Phys. Rev., 1960, 120, 150.6o C. A. Coulson and A. H. Neilson, Proc. Phys. SOC., 1961, 78, 831.62 G. L. Caldow and C . A. Coulson, Proc. Cambridae Phil. SOC., 1961, 57, 341.W. Scherr, J .Chem. Phys., 1960, 33, 317."P.-O. Lowdin, J. MoZ. Spectroscopy, 1959, 3, 46STEWART : WAVE-MECHANICAL CALCULATIONS 21more sophisticated procedures encounter considerable difficulty with increasein size.TABLE 4. Calculated ground-state energies (H) of lithium and berglliumWave function Lithium BerylliumSimplest analytical [equation (13)] -7.41792 * -14.552 pSelf-consistent -field - 7.43273 - 14.5730217-Term correlated function -7.47608 fSuperposition of configurations 39 - 7.477 10 - 14.66090Observed - 7.47807 - 14.66741Pluvinage 41 - 7-395*Ref. 13.7 Ref. 41.$ H. M. James and A. S. Coolidge, Phys. Rev., 1936, 49, 688.The only method of improving on Hartree-Fock wave functions whichadmits of general extension is the method of superposition of configura-tions.With the use of basis functions of s, p , d , f, and g symmetry, this hasbeen applied by Weiss 39 to lithium (45 configurations) and beryllium (55configurations) and by Watson 53 to beryllium (37 configurations). Theenergies which Weiss calculated-the best so far obtained for these twoatoms-are given in Table 4 for comparison with the results of less formidablecalculations. The value which James and Coolidge obtained for lithium25 years ago is included as a reminder that remarkable successes wereachieved in quantum chemistry before the advent of the electronic com-puter.Walsh and Borowitz’s 41 extension of Pluvinage’s 43 perturbationmethod to three-electron systems provides interesting mathematical analysis,but gives a poorer result than the simplest variational calculation.Using fairly simple open-shell wave functions analogous to those theydevised for two-electron systems,33 Ritter, Pauncz, and Appe1S4 have studiedthe ls2ns 2X states (n = 2,3,4,5) of the series Li to P6+.They obtainedground-state energies in error by about 0.01 H for each unit of 2; but theerrors in their transition energies and ionization energies (in the sense ofKoopmans’s theorem 19) were only about one-tenth as large.Linderberg and Shull 55 have made an interesting analysis of correlationin three- and four-electron atoms and ions, finding K-shell correlation tobe largely radial (as in two-electron systems), but L-shell correlation essen-tially angular; i.e., they found configurations in which the 2 9 electrons arekept on opposite sides of the nucleus much more effective in improving thecalculated energy than configurations in which the 2s2 electrons are kept atdifferent distances from the nucleus.Atoms with 2 > 4.-This section is concerned solely with self-consistent-field calculations, for which automatic computer programmes have beenavailable for some years.Although the possibilities of accurate numericalintegration have not been neglected,17, 56 almost all recent work has been53 R. E. Watson, Phys. Rev., 1960, 119, 170.64Z. W. Ritter, R. Pauncz, and K. Appel, J. Chem. Phys., 1961, 35, 571.65 J. Linderberg and H. Shull, J. Mol. Spectroscopy, 1960, 5, 1.a6B. H. Worsley, Proc. Roy. SOC., 1958, A , 247, 39022 GENERAL AND PHYSICAL CHEMISTRYdeveloped in terms of analytical Hartree-Fock wave functions, in which theorbitals are expressed as linear combinations of a small number (usually5-12) of pre-determined basis functions. Precise self-consistent-field wavefunctions are now available for a great variety of atoms and ions with 2as high as 36, and these have superseded the relatively inexact functionspreviously determined by numerical integration. Calculations have beencarried out not only for free atoms but for atoms in perturbing field~.~7, 58Watson and Freeman 18, 59 have given references to recent publications,and have listed the many uses to which the results have been put (notablythe calculation of scattering factors 60-63).has written a mostinformative introduction to this work.The following results 64 for P and F- are typical of the accuracy attain-able :SlaterTotal electronic energy (H) F F-Calc.- 99.40792 - 99.45891Obs. - 99.8096 - 99.9426The error is about twice as large as in a thorough-going calculation based onsuperposition of configurations. G5For atoms of high atomic number, where no spectroscopic determina-tions of total electronic energy are available, self-consistent-field wave func-tions can be checked by evaluation of ionization energies, transition energies,and multiplet separations. These are severe tests, for they involve energydifferences far smaller than the error in the total electronic energy, but theresults give little cause for lack of confidence. Unaccountably, ionizationenergies (and electron affinities (j4) calculated by means of Koopmans'theorem,lg unlike those calculated as the differences of state energies, areusually in excellent agreement with experiment.An atomic Hartree-Fock calculation is described as " restricted " if itis based on the minimum number of radial functions (one for each of Is, 29,2p, .. .), and " unrestricted '' if this condition is relaxed in the interests offlexibility or orthogonality. Technical problems arise in the solution of anunrestricted Hartree-Fock equation, for the wave function cannot then beexpressed strictly as a single determinant. The problems and means ofevading them have been discussed by various authors.l0* 66Hydrogen Molecule-ion.-Because of its unique simplicity the diatomichydrogen cation, H2+, has always been a popular system on which to testquantum-chemical techniques.Exact solutions 67 to the Schrodingera7L. C. Allen, Phys. Rev., 1960, 118, 167.58 J. H. Wood, Plzys. Rev., 1960, 117, 714.5 9 R . E. Watson and A. J. Freeman, Phys. Rev., 1961, 123, 521.soA. J. Freeman, Acta Cryst., 1959, 12, 274, 929; 1960, 18, 190, 618.R. E. Watson and A. J. Freeman, Acta Cryst., 1961, 14, 27; A. J. Freeman andR. E. Watson, ibid., p. 231; A. J. Freeman and J. H. Wood, ibid., 1959, 12, 271.62B. Dawson, Acta Cryst., 1960, 13, 403; 1961, 14, 1117, 1120, 1271.63 C. M. Womack, J. N. Silverman, and F. A. Matsen, Acta Cryst., 1961, 14, 744.64L. C. Allen, J . Chem. Phys., 1961, 34, 1156.6sM.J. M. Bernal and 8. F. Boys, Phil. Trans., 1952, A, 245, 139.66R. K. Nesbet and R. E. Watson, Ann. Physique, 1960, 9, 260; L. M. Sachs,Phys. Rev., 1960, 117, 1504; W. Marshall, Proc. Phys. SOC., 1961, 78, 113; A. T. Amosand G. G. Hall, Proc. Roy. Soc., 1961, A, 263, 483.67 D. R. Bates, K. Ledsham, and A. L. Stewart, Phil. Trans., 1953, A, 246, 215STEWART : WAVE-MECHANICAL CALCULATIONS 23equation are available for a wide range of internuclear distances, and thesehave been of considerable value in supplementing the minimum-energycriterion for appraising the merits of approximate wave functions.Apart from the lack of spherical symmetry, the feature which makesmolecular calculations so much more difficult than atomic calculations isthe need for evaluating the many-centre integrals which arise when themolecular wave function is built up from atomic wave functions with originsof co-ordinates at the various nuclei. This difficulty can sometimes beovercome by writing the molecular wave function as a linear combinationof basis orbitals having a common origin of co-ordinates (usually the centreof the molecule).In the case of H2+ this consists in treating the molecularwave functions as perturbed “ united-atom ” wave functions for He+.Howell and Shull 38 investigated the expansion of the wave functionfor H,+ as a linear combination of single-centre Epstein 34 functions, butfound the convergence discouragingly slow. Using the &st six basis func-tions of s symmetry they obtained a ground-state energy of -1.01842 H,and this they reduced to -1.09563 H by the addition of the first five dfunctions and the first g function.Spheri-cally symmetrical basis functions are not, of course, well suited to a moleculewith axial symmetry, at least in the ground state. In the excited states,where the effective size of the charge distribution is high in relation to theinternuclear distance, convergence is relatively rapid, and Howell and Shullobtained more promising results.Cohen, Coulson, and Fox 68 have solved the convergence problem bytaking the one-centre basis functions to be products of Legendre angularfactors and completely flexible radial factors (determined by numericalintegration). Using only four basis functions they obtained very goodvalues for the ground-state energy (-1-09994 H) and for the oscillatorstrength of the transition to the first excited CT state.[A discrepancybetween the results of Howell and Shull 38 and Cohen, Coulson, and Fox 68and an earlier result obtained by Chen 69 has been resolved by G&~p&r.~0]In a conventional two-centre molecular-orbital calcul&tion on H, +Pritchard and Sumner 36 have demonstrated convincingly the superiorityof Epstein 34 basis functions (which form a complete set *) over the usua.1hydrogen-like functions.In a straightforward molecular-orbital study of the lowest nu state ofHZ+, Sovers and Kauzmann 71 have shown that the simplest possible 2pnwave function is greatly improved by the superposition of a d configuration.A calculation remarkable for both its simplicity and its success has beencarried out by Scrocco and Tomasi.72 They obtained a ground-state energyThe exact value is - 1.10262 H.68 M.Cohen, C. A. Coulson, and L. Fox, Proc. Cambridge PhiE. Soc., 1961, 57,asT. C. Chen, J . Chem. Phys., 1958, 29, 347.? O R . G&sp&r, Acta Phys. Acad. Sci. Hung., 1960, 11, 295.72E. Scrocco and 6. Tomasi, MoZ. Phys., 1961, 4, 193.96.Sovers and W. Kauzmann, J . Chem. Phys., 1961, 35, 652.*Two complete sets in fact in Pritchard and Sumner’s calculations. “Over-completeness ” is a potential source of d%culty, but not one which Pritchard andSumner experienced24 GENERAL AND PHYSICAL CHEMISTRYofbyin- 1.1005 a merely by replacing the customary 1s atomic orbital exp( -cr).exp(-cr - br cos 0).Jepsen and Hirschfelder 73 have estimated the coupling terms neglectedthe Born-Oppenheimer approximation.Robinson 74 has studied the hydrogen molecule-ion as a problem inperturbation theory.Hydrogen Molecule.-The hydrogen molecule continues to be studiedfar more intensively, and with far greater success, than any other molecularsystem. The results of some recent calculations are given in Table 5, alongwith two early results (recalculated 75) for comparison.TABLE 5. Calculated ground-state energy of the hydrogen molecule( R = Re = 1.4008 B)Wave function Energy (a)Simplest molecular-orbital 75Self-consistent-field : closed shell 22* 25Self-consistent-field : open shell 25Molecular-orbital with 1s configuration interaction 75Molecular-orbital with Is, 28, 2p configuration interaction 76Wave function with correlation factor: closed shell asWave function with correlation factor: open shell a5Exact 28Observed- 1.1282 - 1.13357- 1.14182- 1.14796-1.1672- 1.17257- 1.17296- 1.17445- 1.17444 f 0.00003The well-known wave function which James and Coolidge 77 used in1933 was an expansion in elliptical co-ordinates of the formwhereandR being the internuclear distance, and r, and rl, distances measured fromthe two nuclei.The terms in the expansion (31) arise from various choicesof integral exponents, p , q, r , s, p. By considerably extending the expan-sion lengths which James and Coolidge were able to use, Kolos and Root-haan 22 have obtained wave functions which can be regarded as exact overa wide range of R (subject to the limitations of the Born-Oppenheimerapproximation). The value quoted in Table 5 was obtained from st 50-termexpansion, but a 14-term expansion gives an energy only 0.0002 H in error.The self-consistent-field energies in Table 5 were calculated by omittingthe r,, terms in expression (32), and, in the case of the conventional closed-shell calculation, putting p = ry q = s.It is interesting to note thatCoulson 78 obtained -1.13318 H in the first molecular self-consistent-fieldcalculation ever carried out (by what is now known as Roothaan's lo method).t = (r, + rd/R, q = (r, - rb)/RY73 D. W. Jepsen and J. 0. Hirschfelder, J . Chem. Phys., 1960, 32, 1323.74P.D. Robinson, Proc. Phys. Xoc., 1961, 78, 537.75H. Shull, J . Chem. Phys., 1959, 30, 1405.76A. D. McLean, A. Weiss, and M. Yoshimhe, Rev. Mod. Phys., 1960, 32, 211.7 7 H . M. James and A. S. Coolidge, J . Chem. Phys., 1933, 1, 825.78 C. A. Coulson, Proc. Cambridge Phil. SOC., 1938, 34, 204STEWART : WAVE - M E CH AN I C AL C AL C U L AT1 0 N S 25The possibility of using numerical integration for solving the Hartree-Fockequation for hydrogen has been examined by Berthier and May~t.~QKolos and Roothaan 22 have compared the mean values of r:, 3x; - Y:,lly 1/r12, and rlz given by the self-consistent-field wave function with theexact values, and have found reasonably good agreement in the first threecases. This suggests that self-consistent-field wave functions may give satis-factory values for the diamagnetic susceptibilities (Larmor terms) andmolecular quadrupole moments of larger molecules for which more accuratewave functions are unattainable.The wave functions with correlation factors listed in Table 5 wereobtained 2 5 (by analogy with the corresponding functions for helium z4) bytruncating the expansion (31).Recent accurate work on the ground state of hydrogen not representedin Table 5 includes the use of Gaussian orbitals (Longstaff and Singersingle-centre wave functions (Hagstrom and Shull 81), and " product atomicorbitals " (Ellison and Companion 82).Shull 75 has made a detailed com-parison of various wave functions in terms of " natural spin-orbitals 2,'y andhas discussed the use of the terms " covalent " and " ionic " in the ele-mentary analysis of hydrogen wave functi0ns.~3 Ladik 84 has evaluatedrelativistic corrections.McLean, Weiss, and Yoshimine 76 have compiled a valuable bibliographyof work on the ground state of the hydrogen molecule.Calculations on the lower excited states of hydrogen have been carriedout by Kolos and Roothaan 22 (3&!, lXC,+, Z;), by Davidson 85 (Z;) andby Tschudi and Cohan s6 ('EL).The last two calculations exemplify thedifficulty of describing excited molecular states in terms of atomic groundstates.Using the first allowed transition of hydrogen as an example, Ehrensonand Phillipson 87 have demonstrated the impossibility of calculating oscil-lator strengths from simple wave functions.Diatomic &leculc%.-Allen and Karo s8 have provided a comprehensivesurvey and bibliography of non-empirical calculations on small molecules,radicals, and ions published by mid-1959.Systems studied more recentlyinclude H,- (Fischer-Hjalmars s9), He, + (Csavinszky 9, LiH (Kar0;~1Robinson, Stuart, and Matsen;92 Rfoccia 93), BeH (Moccia;93 Aburto etJ. V. L. Longstaff and K. Singer, Proc. Roy. Soc., 1960, A, 258, 421.S . Hagstrom and H. Shull, J. Chem. Phys., 1959, 30, 1314.79G. Berthier and M. Mayot, J . Chim. phys., 1959, 56, 504.saF. 0. Ellison and A. L. Companion, J . Chem. Phys., 1959, 31, 285.83H. Shull, J . Amer. Chem. SOC., 1960, 82, 1287.84 J. Ladik, Acta Phys. Acad. Sci. Hung., 1961, 13, 123.85E.R. Davidson, J. Chem. Phys., 1961, 35, 1189.86C. S. Tschudi and N. V. Cohan, J . Chenz. Phys., 1961, 34, 401.87 S. Ehrenson and P. E. Phillipson, J . Chem. Phys., 1961, 34, 1224.L. C. Allen and A. M. Karo, Rev. Mod. Phys., 1960, 32, 275.8g I. Fischer-Hjalmars, Arkiv. Fys., 1959, 16, 33.slA. M. Karo, J . Chem. Phys., 1960, 32, 907.s2 J. M.'Robinson, J. D. Stuart, and F. A. Matsen, J. Chenz. Phys., 1960, 32, 988.93R. Moccia, Gazzetta, 1960, 90, 955, 968.s4 S. Aburto, R. Gallardo, R. Muiioz, R. Daudel, and R. Lefebvre, J . Chim. phys.,Csavinszky, J. Chem. Phys., 1959, 31, 178.1959, 56, 56326 GENERAL AND PHYSICAL CHEMISTRYCH (Masse 95), C, (Clementi 96), CO (Brion, Moser, and Ne~bet;~' Hurley 98),N, (Clementi 9g), NO (Brion, Moser, and Yamazaki loo), OH (Freeman 101),OH and OH- (GAsphr and Tamhssy-Lentei lo,), HF (Nesbet lo3), F, andF2+ (Hijikata lo*).The interaction of two helium atoms has been examinedby Moore,lo5 by Brigman, Brient, and Matsen,106 and by Ransil,lo7 andother long-range interactions by Dalgarno and his co-workers, lo8 by Hirsch-felder and L0wdin,lo9 by Eliason and Hirschfelder,llo and by Bingel, Preuss,and Schmidtke .The simplest single-configuration molecular-orbital wave function for theground state of the hydrogen molecule (Table 5, first function),Y = @( l)@(2)= [exP(-cral) 3- exp(--cr,,)lCexp(--cr,,) + exp(--cr,,)l, (33)has served as a model for a considerable number of calculations on the groundstates of homonuclear and heteronuclear diatomic molecules, radicals, andions formed from atoms with 1 < 2 < 10.In the majority of these cal-culations the atomic orbitals from which the molecular orbitals are con-structed are taken to be single ls, 28, and 2p functions of the Slater type(hybridized where necessary), and superposition of configurations is notconsidered. Work of this kind is typified by Ransil's 112 systematic studyof twelve diatomic molecules with closed-shell ground states. Total elec-tronic energies are usually calculated with an error of only 0.5--1.5% (muchas in the corresponding atomic systems); but dissociation energies are badlyunderestimated and excitation energies seldom reported.* It is significantthat the use of improved (e.g., Hartree-Fock) atomic orbitals seems to im-prove total molecular energies but not dissociation energies.88 Calculationsof molecular energy as a function of internuclear distance have been made,and used with some success in the estimation of spectroscopic constants.114J.-L. Masse, J . Chim. phys., 1961, 58, 372.gsE. Clementi, Gazzetta, 1961, 91, 717.97 H. Brion and C. Moser, J . Chem. Phys., 1960, 32, 1194; H. Lefebvre-Brion, C.Moser, and R. K. Nesbet, ibid., 1960, 33, 931; 1961, 34, 1950.98 A. C. Hurley, Rev. Mod. Phys., 1960, 32, 400.g9E. Clementi, Gazzetta, 1961, 91, 722.100 H. Brion, C. Moser, and M. Yamazaki, J . Chem. Phys., 1959, 30, 673; 1960, 33,1871; M. Yamazaki, M. Sakamoto, K. Hijikata, and C. C. Lin, ibid., 1961, 34, 1926.1olA. J. Freeman, Rev. Mod. Phys., 1960, 32, 273.loe R.GBsp&r and I. Tamhssy-Lentei, Acta Phys. Acad. Sci. Hung., 1959, 10, 149.103 R. K. Nesbet, Rev. Mod. Phys., 1960, 32, 272.104K. Hijikata, J . Chem. Phys., 1961, 34, 221, 231.l o s N . Moore, J . Chem. Phys., 1960, 33, 471.lo6 G. H. Brigman, S. J. Brient, and F. A. Matsen, J . Chem. Phys., 1961, 34, 958.107B. J. Ransil, J . Chem. Phys., 1961, 34, 2109.l o 8 A. Dalgarno and A. L. Stewart, Proc. Roy. SOC., 1960, A , 254, 570; A. Dalgarno109 J. 0. Hirschfelder and P.-0. Lowdin, Mol. Phys., 1959, 2, 229.lroM. A. Eliason and J. 0. Hirschfelder, J . Chem. Phys., 1959, 30, 1397.ll1 W. A. Bingel, H. Preuss, and H.-H. Schmidtke, 2. Naturforsch., 1961, Ma, 435.llaB. J. Ransil, Rev. Mod. Phys., 1960, 32, 239, 245; S. Fraga and B. J. Ransil,lrsE.T. Stewart, Proc. Phys. Soc., 1960, 75, 402.ll4S. Fraga and B. J. Ransil, J . Chem. Phys., 1961, 35, 669.* It is, of course, impossible to calculate a wide spectrum of molecular excitationenergies with wave functions built up solely from ground-state atomic orbitals (cf.hydrogen 113).and A. E. Kingston, Proc. Phys. SOC., 1961, 78, 607.J . Chem. Phys., 1961, 34, 727STEWART : WAVE-MECHANICAL CALCULATIONS 27The terms ‘‘ Hartree-Fock ” and “ self-consistent-field ” serve a veryuseful purpose in characterizing atomic and molecular orbitals of optimumform in single-configuration wave functions, and it is thus most unfortunatethat they have come to be applied to wave functions of the type describedin the previous paragraph; these are no more like HartreeFock wavefunctions than is function (33) or the first function in Table 1.Thenomenclature of quantum chemistry is cumbrous enough without the intro-duction of tautological absurdities such as “ accurate self-consistent-fieldorbitals.”In one of the few genuine self-consistent-field calculations on molecularsystems to be reported, Nesbet lo3 has found the error in the computedelectronic energy of hydrogen fluoride to be reduced considerably by theuse of orbitals built up from an adequate set of basis functions.Surprisingly few quantum- chemical calculations include an examinationof electron-density distribution. R o u x , ~ ~ ~ however, has calculated thechange in charge distribution which occurs when the molecules H,, O,, N2,F,, NO, and CO are formed from their constituent atoms.The results offerlittle support for elementary theories of chemical bonding.Polyatomic Molecules.-The majority of calculations on polyatomicmolecules, radicals, and ions, as on the corresponding diatomic systems,embody the smallest possible number of atomic orbitals (Is, 28, Zp), and aremodelled on the simplest wave function for the ground state of hydrogen(sometimes with limited superposition of configurations). There is muchthe same agreement between theory and experiment as for diatomic mole-cules, provided three- and four-centre integrals are evaluated accurately.lfsRecent papers not listed in Allen and Karo’s 88 bibliography report workon CH, and CH, (Padgett and Krauss 117); C,H, (McLean;llG Burnelle ll*);C3, N3-, NO,+ (Clementi l19); HF2- (Clementi;l19 Bessis and Bratoi lZ0);H,O (GAspAr and TamAssy-Lentei ; l o 2 McWeeny and Ohno 121) ; NH, +(Lorquet 122); and HCHO (Goodfriend, Birss, and Duncan lZ3).Because of its nearly spherical symmetry, the methane molecule has beenthe subject of more refined calculations l Z 4 than most other polyatomicmolecules. The latest of these (Albasiny and Cooper 125) gives a totalelectronic energy differing by 1.5% ( 0 .6 ~ ) from the observed value.Boys 23 has described the problems involved in the completely automatic115 M. ROUX, J . Chim. phys., 1960,57, 53; M. ROW, M. Cornille, and G. Bessis, &bid.,1961, 58, 389; S. BratoB, R. Daudel, M. ROUX, and M. Allavena, Rev. Mod. Phys.,1960, 32, 412.116 A.D. McLean, J. Chem. Phys., 1960, 32, 1595; A. D. McLean, B. J. Ransil, andR. S. Mulliken, ibid., p. 1873.l17A. Padgett and M. Krauss, J. Chem. Phys., 1960, 32, 189.llSL. Burnelle, J . Chem. Phys., 1960, 32, 1872; 1961, 35, 311.119 E. Clementi, J . Chem. Phys., 1961, 34, 1468.lZo G. Bessis and S. Bratoi, J . Chim. phys., 1960, 57, 769.lZ1R. McWeeny and K. A. Ohno, Proc. Roy. SOC., 1960, A , 255, 367.lZ2 J.-C. Lorquet, Rev. Mod. Phys., 1960, 32, 312; J.-C. Lorquet and H. Lefebvre-Brion, J . Chim. phys., 1960, 5’7, 85.lZ3P. L. Goodfriend, F. W. Birss, and A. B. F. Duncan, Rev. Mod. Phys., 1960,32, 307.1241. M. Mills, Mol. Phys., 1958, 1, 99, 107; 1961, 4, 57; R. K. Nesbet, J. Chsm.Phys., 1960, 32, 1114; A. F. Saturn0 and R. G.Pam, ibid., 1960, 33, 22.lZ5E. L. Albasiny and J. R. A. Cooper, Mol. Phys., 1961, 4, 35328 GENERAL AND PHYSICAL CHEMISTRYcomputation of molecular properties by extensive superposition of configura-tions, and has presented the results of specimen calculations on the methyl-ene radical 126 and the formaldehyde m01ecule.l~~ He has also exploredthe possibility of constructing localized orbitals approximately invariantfrom one molecule to another.128Lowdin 129 has discussed the properties of wave functions which gobeyond the Hartree-Fock formulation.E. T. S.3. IOLECULAR-ENERGY TRANSFER IN GASESTHERMAL energy may be stored by molecules in translational, rotational,and vibrational motion. Transfer of energy from internal modes of motion,particularly vibration, to translation is not necessarily an efficient processcollision-wise. This means that the thermodynamic properties of gases maybe time-dependent, an important phenomenon from the point of view ofgas dynamics.Further, since molecules must become highly excited vibra-tionally in order to decompose, the connexion between energy transfer andchemical kinetics is a close one. The subject is therefore of interest to bothphysicists and chemists. It was last treated in these Reports for 1958,lbut the present Review is more limited in scope than its predecessor. Energytransfer in liquids and solutions was also treated in 1958. The presentReporter believes, however, that it is not necessarily appropriate to treatthe liquid and the gas phase together in this connexion, and so he dealshere exclusively with gases, for the period from late 1958 to October1961.Since 1958 two books have dealt with this subject, one mainly with ultra-sonic methods but including a detailed treatment of the theory of vibrationalenergy transfer,2 the other covering nearly the same ground as the presentR e p ~ r t .~Experimental Methods.-The classical ultrasonic methods of measuringrelaxation times for vibrational-translational energy transfer continue tobe used. Edmonds and Lamb4 have described a new method of measuringsound absorption in gases and applied it to a number of polyatomic mole-cules. The use of the shock tube for energy-transfer studies at high tem-peratures has increased rapidly, and Gaydon and his co-workers 5-7 havedeveloped a method of measuring vibrational temperatures in shocks byJ.M. Foster and S. F. Boys, Rev. Mod. Phys., 1960, 32, 305.wJ. M. Foster and S. F. Boys, Rev. Mod. Phys., 1960, 32, 300, 303.1Z8S. F. Boys, Rev. Mod. Phys., 1960, 32, 296.12@ P.-0. Lowdin, Rev. Mod. Phys., 1960, 32, 328.1 B. Stevens, Ann. Reports, 1958, 55,‘80.8 K. F. Herzfeld and T. A. Litovitz, Absorption and Dispersion of UltrasonicT. L. Cottrell and J. C. McCoubrey, “ Molecular Energy Transfer in Gases,”4 P. D. Edmonds and J. Lamb, Proc. Phgs. SOC., 1958, 72, 940.5 J. G. Clouston, A. G. Gaydon, and I. I. Glass, Proc. Roy.Soc., 1958, A , 248, 429.6 A. G. Gaydon and J. Hurle, Eighth Combustion Symp., Pasadena, in the press.7 A.G. Gaydon and I. R. Hurle, Proc. Roy. SOC., 1961, A , 262, 38.Waves,” Academic Press, New York, 1959.London, Butterworths Scientific Publns., 1961COTTRELL : MOLECULAR-ENERGY TRANSFER I N GASES 29spectrum-line reversal. It appears that excitation temperatures of metalsare in equilibrium with the vibrational rather than the translational tem-peratures. Direct spectroscopic measurement of the population of lowexcited vibrational levels has been achieved by several workers.8, Theoptic-acoustic effect,lO which has long promised to give information aboutrelaxation times, has not yet done so, but a paper on the theory hasappeared in Canada.11 The same results were obtained independently inLondon.Vibra-tional-temperature measurement in a shock tube has yielded values of0-4 psec. at 2280" H, and 0.8 psec.at 2600" K for the vibrational-relaxationtime, z. These times seem surprisingly short. The most recent results l3on rotational relaxation confirm earlier work.Vibrational-relaxation times have been measured by usingthe spectrum-line-reversal method in shocked gas,5, 6 with results in agree-ment witn those of previous work. l4 Water-nitrogen collisions were be-tween 10 and 100 times more effective than nitrogen-nitrogen collisions indeactivating vibrationally excited nitrogen. Rotational-relaxation times inagreement with earlier work have been determined.15Oxygen. Direct measurement of the vibrational-relaxation time bymeans of the propagation of low-frequency sound l8 has confirmed an earlierconclusion by the indirect method 1' that z = 3.2 x loA3 sec.On theother hand, a further determination18 by the indirect method (that is,by extrapolation to zero impurity) gave the considerably longer result,z = 1.8 x 10-2 sec. Mixtures were also studied, hydrogen-oxygen colli-sions being 3 x lo3, deuterium-oxygen 3 x lo2, and helium-oxygen3-5 x 102 times more effective than oxygen-oxygen collisions. Spectro-scopic measurements l9 on shocked oxygen-argon mixtures from 1200" to7000" K gave z for oxygen-oxygen collisions close to those found earlier l4above 2000" K, but a little longer at temperatures around 1200" K. Oxygen-oxygen collisions were about 5 times more effective than oxygen-argoncollisions, the ratio being independent of temperature.Rotational relaxa-tion has also been studied.15Vibrational relaxation in the B2Cf excited state of cyanidehas been detected spectroscopically in a shock tube. z varies from 42 psec.a t 6 3 0 0 " ~ to 14 psec. a t 9 5 5 0 " ~ . ~ ~Curbon monoxide. Shocked carbon monoxide has been studied byExperimental Results €or Low-lying Energy States.-Hydrogen.Nitrogen.Cyanide.N. Basco, A. B. Callear, and R. G. W. Norrish, Proc. Roy. Soc., 1961, A, 260, 459.9F. Robben, J . Chem. Phys., 1959, 31, 420.lo M. E. Delany, Science Progr., 1959, 47, 459.l1 R. Kaiser, Cannd. J . Phys., 1959, 37, 1499.12M. E. Delany, Thesis, London, 1959.13H. D. Parbrook and W. Tempest, J . Acoust. SOC. Amer., 1958, 30, 985.l* S. J. Lukasik and J. E.Young, J . Chem. Phys., 1957, 27, 1149; V. Bhckman,16M. Greenspan, J . Acoust. SOC. Amer., 1959, 31, 155.l6 F. A. Smith and W. Tempest, J . Acoust. SOC. Amer., 1961, 33, 1626.I7H. Knotzel and L. Knotzel, Ann. Phys., 1948, 2, 393.18J. G. Parker, J . Chem. Phys., 1961, 34, 1763.19M. Camac, J . Chem.. Phys., 1961, 34, 448.2OW. Roth, J. Chem. Phys., 1959, 31, 720.J . Fluid Mechanics, 1956, 1, 6130 GENERAL AND PHYSICAL CHEMISTRYseveral workers.6, ' 9 21 The longest reported z is about 6 x 10-4 sec. at1500" K , ~ O decreasing to about 2 psec. at 4900" K. Water produces a markedreduction in z, and carbon dioxide produces a slight reduction; hydrogen,nitrogen and oxygen are stated to have no effect.22Nitric oxide. Vibrational relaxation in the ground ( 2Li!) electronic statehas been studied by sound absorption at room temperature,23 by kineticspectroscopy of flashed gas at room temperature,8 and by spectroscopicshock-tube experiments from 450 to 1300" K.' All these investigations showrelaxation times many powers of ten shorter than predicted theoretically orfound for nitrogen, oxygen, or carbon monoxide, and this anomaly has beendiscussed.24 The values obtained are in the microsecond region at roomtemperature.The egect of added gas has also been studied:8 water isabout 20 times as efficient as nitric oxide, carbon dioxide about half asefficient, carbon monoxide about a tenth as efficient, and nitrogen andhydrogen are much less efficient. The situation here is complicated byspin-orbit relaxation.Vibrational relaxation in the excited (A2X +) state of nitric oxide has beenstudied spectroscopically for the shocked gas.25 The relaxation times forthe 2-1 and 1-0 vibrational transitions at 6950" K are 6.7 and 12.5 psec.,respectively. For the 1-0 transition, the transition probabilities percollision are 3 x a t 10,000"~.Chlorine. Vibrational-relaxation times in chlorine have been remeasuredby the sound absorption method.26 z a t low temperature (e.g., 4-9 psec.a t 2 9 8 " ~ ) is in agreement with earlier work, but a t higher temperatures(400-500" K) is rather longer than was thought earlier (e.g., 2.3 psec. at4-40" E, compared with an earlier value of 1-6 psec. a t 415" K 27). A newmeasurement 28 of velocity dispersion over a good range gives a slightlyshorter value for z at room temperature than was obtained by others.at 5 0 0 0 " ~ and 3 xHydrogen chloride.Rotational relaxation only has been studied. 29Bromine and iodine. Vibrational relaxation has been studied by soundabsorption 26 and dispersion.28 For bromine, dispersion gives z twice asgreat as is given by absorption, and for iodine about seven times as great.The only new results since 1958 are some observationsa t ordinary density 30 in general agreement with previous work, and somemeasurements at high density 31 which show that if intermolecular attractiveforces are taken into account good agreement is obtained between the col-lision efficiencies in the gas and the liquid phase.The relaxation time of the 2223 cm.-l band has beenCarbon dioxide.Nitrous oxide.21M.Windsor, N. Davidson, and R. Taylor, 7th Sjmp. on Combustion, Butter-22D. L. Mathews, J . Chem. Phys., 1961, 34, 639.23 H. J. Bauer, H. 0. Kneser, and E. Sittig, J . Chem. Phys., 1959, 30, 1119.24F. Robben, P. R. Monson, and J. J. Allport, J . Chem. Phys., 1960, 33, 630.Z5W. Roth, J . Chem. Phys., 1961, 34, 999, 2204.26 F. D. Shields, J . Acoust. SOC. Amer., 1960, 32, 180.27A. Eucken and R. Becker, 2. phys. Chem., 1934, B, 27, 235.2sE. G. Richardson, J . Acoust. SOC. Amer., 1959, 31, 152.=OM. A. Breazeale and H. 0. Kneser, J . Acoust. SOC. Amer., 1960, 32, 885.%OF. D. Shields, J . Acoust. SOC. Amer., 1959, 31, 248.91 W. M. Madigosky and T. A. Litovitz, J . Chem. Phys., 1961, 34, 489.worths Scientific Publns., London, 1958, p.80COTTRELL : MOLECULAR-ENERGY TRANSFER IN GASES 31found by an infrared method 32 to be sec., much longer than the overallz found by ultrasonic methods. The established ultrasonic results havebeen further ~onfirmed.~3Carbon disulphide. z has been redetermined over the temperaturerange 233433'9, by the absorption technique.34 The results a t highertemperatures are new, those at lower temperatures agree with previouswork.Sulphur dioxide. Some doubt has been cast 35 on earlier 36 gas data forsulphur dioxide. Until evidence for these doubts has been fully published,the earlier data must stand, particularly as they have recently been inde-pendently confirmed. 37 There are two relaxation times for this molecule,and the more recent values for these quantities are z1 = 6 x sec.,z, = 1.2 x 10-6 sec.The previous 36 result for z, was 0.6 x sec.,but this relaxation time is the more subject to experimental error. n-Hex-ane is a particularly effective energy-transfer catalyst for sulphur dioxide.37Ammonia. The most recent investigation3* suggests that z for thismolecule is very short.Boron trijuoride. Sound-absorption measurements* lead to z = 0.09psec. a t 298" K.Silane. Ultrasonic velocity measurements 39 at 298" K give z = 0.19psec. for tetradeuteriosilane, and 0.11 psec. for silane. These results showthe same tendency as those for the methane analogues, discussed below.SuZphur hexajluoride. Recent sound-velocity measurements 40 a t 301 " Klead to z = 0.78 psec., in fair agreement with previous work.Hethane.Ultrasonic velocity measurements 41 at 2 9 8 " ~ give z as3.9 psec. for tetradeuteriomethane and 2.1 psec. for methane. The latterfigure is slightly greater than the previous highest result., The CD, : CH,ratio does not agree with expectation based on simple vibrational-transla-t,ional energy transfer, but might be due to rotational effects.Carbon tetrajuoride. Sound-absorption measurements have confirmedearlier sound-velocity results.Methyl chloride. Earlier work from Lambert's school has now beensuperseded.3, *2 Sound-absorption measurements have confirmed othersound-velocity results.43Chlorodijuoromethane, dichlorodi$uoromethane, chlorotrijuoromethune, andbromotrijuormethane.Ultrasonic velocity measurements 43 give relaxationtimes over a temperature range.Methyl bromide. Recent ultrasonic measurements 43 give results in32G. Gauthier and J. Marcoux, Cunad. J . Phys., 1961, 39, 1130.a3R. Holmes, H. D. Parbrook, and W. Tempest, Acustica, 1960, 10, 155.84 J. C. Gravitt, J . Acoust. SOC. Amer., 1960, 32, 560.35M. C. Henderson, quoted in ref. 31.s6 J. D. Lambert and R. Salter, Proc. Roy. SOC., 1957, A, 243, 78.37 J. C. McCoubrey, R. C. Milward, and A. R. Ubbelohde, Proc. Roy. SOC., 1961,38 J. D. Lambert and R. Salter, Proc. Roy. SOC., 1959, A, 253, 277.40 J. C. McCoubrey, unpublished work.41 T. L. Cottrell and A. J. Matheson, Proc. Chem. SOC., 1962, 17.r2A. J. Edwards, B.Sc. Thesis, Oxford, 1959.43R.Amme and S. Legvold, J . Chem. Phys., 1959, 30, 163.A, 264, 299.L. Cottrell and A. J. Matheson, unpublished work32 GENERAL AND PHYSICAL CHEMISTRYagreement with earlier values. z for bromotrideuteriomethane is nearlydouble the value for bromomethane.38Methylene bromide. A set of three separate relaxation times has beenpostulated to explain the ultrasonic-velocity results for this compomd,44and it has been shown that this scheme leads to complete disagreementbetween theory and experiment.4s As the theory is fairly well established,further experimental work seems called for.Ethane. A double-dispersion region in this compound is well estab-l i ~ h e d , ~ ~ , 46 the more reliable results at 2 9 6 " ~ being z1 = 1.4 x 10-8 sec.,tz = 0.12 x sec.Ethyl fluoride, 1,l-difluoroethaneY hexaJEuoroethane, ethyl chloride, and1 , l - and 1,2-dichloroethane.All these compounds have been shown by ultra-sonic velocity measurement 38 to have very short relaxation times.1,2- DichZoro-1,1,2,2-tetra$uoroethane. z has been measured by soundabsorption. *Propane, n-butane, isobutam, and mopentune. These compounds haveall been shown to have very short relaxation times,38 only that of propanea t 298" K (z = 0.4 x sec.) being detectable up to 50 Mc. sec.-1 atm.-1.Ethylene. Two more contributions have been made to the mass of dataon this c o m p o ~ n d , ~ ~ ~ 48 and it seems that z a t 298" K is fairly well estab-lished as 0.26 & 0.02 psec. The relaxation time for tetradeuterioethyleneis about half that value, although simple theory 48 suggests it should benot more than a quarter.Tetra- and di-deuterioethylene, water, and di-deuterium oxide are all energy-transfer catalysts for ethylene.48Acetylene. Two recently determined values of z differ by a factor ofnearly 2, velocity dispersion 38 giving z = 7 x sec., and sound absorp-tionButadiene. The relaxation time has been measured by the sound-absorption m e t h ~ d . ~Dimethyl ether. The relaxation time is very short and it is uncertainwhat modes are concerned.38Cyclopropane. Sound-absorption measurements have confirmed earlierresults.Theory of Vibrational-energy !Crans€er.-No fundamentally new theo-retical discussion of the problem has appeared in the period under review,for the good reason that the basic theory put forward by Zener in 1931 isessentially correct.49 The amplification of it described in detail by Herzfeldand his co-workers puts it in a form which is convenient to use. Themodifications which have been discussed are concerned with refinement intwo main directions: fist, in order to discuss low-energy interactions betweenpolyatomic molecules more accurately and, secondly, in order to extendits usefulness to higher-energy states and eventually t o reaction.giving 12 x 10-8 sec.44N.J . Meyer, J . Chenz. Phys., 1960, 33, 487.45P. G. Dickens and D. Schofield, J. Chem. Phys., 1961, 35, 374.4 6 L. M. Valley and S. Legvold, J . Chcm. Phys., 1960, 33, 627.4 7 J. C. Gravitt, J . Acoust. SOC. Amcr., 1960, 32, 1455.48 G.H. Hudson, J. C. McCoubrey, and A. R. Ubbelohde, Proc. Roy. Soo., 1961,p°C. Zener, Phys. Rev., 1931, 37, 556; 38, 277.A , 284, 289COTTRELL : MOLECULAR-ENERGY TRANSFER IN GASES 33The theory in its simplest form neglects the attractive part of the inter-molecular potential and the (‘ symmetrisation ” of approach and recessionvelocities. It is necessary to take both these factors into account in orderto secure agreement with experiment.50 If this is done by the amplificationof Tanczos’s method 51 in applications to polyatoniic molecules, fair agree-ment between calculated and observed results is generally obtained.52 Useof a Morse potential for the intermolecular interaction improves agreementwith experiment for methyl chloride.53 Use of a Lennard-Jones type 28 : 7potential improves agreement with experiment for halogenomethanes ingeneral.54 Vibrational relaxation in carbon dioxide has been treated withparticular reference to the form of the normal modes, with the predictionof two relaxation times.55The classical treatment of one-dimensional inelastic collision with im-pulsive interactions 56 has been followed by a quantum-mechanical one 57in which it is shown that under these conditions there may be vibrationaljumps of more than one quantum.The study of higher-energy interactionshas been carried further by the use of a Morse function for the vibrator.58When transitions to the continuum are taken into account it appears thatthe activation energy for the thermal dissociation of diatomic moleculeswould be expected to be below the bond energy because of breakdown ofthe Boltzman distribution.This problem has also been tackled by manyother workers.Energy-transfer processes in polyatomic molecules are so complicatedthat there is room for empirical correlations of the experimental results,and a particularly interesting study in this field is due to Lambert andSalter.38 They showed that, for molecules in which the fundamental vibra-tion frequencies are so distributed that there is only a small gap betweenthe lowest and the remaining frequencies, vibrational-energy transfer in-volves a single relaxation process. The chief factors affecting the prob-ability of energy transfer are the frequency of the lowest mode and thepresence or absence of a hydrogen atom in the molecule.Molecules con-taining two or more hydrogen atoms s a e r energy transfer much morereadily than do other molecules. This generalisation is supported by animpressive correlation diagram. No firm explanation of this effect was putforward by its discoverers, but it seems possible that it may be linked withthe greater ease of rotational-vibrational energy transfer in molecules withlow moments of inertia.39It has been common in all this work to quote ‘( the number of collisionsrequired” for energy transfer, and to calculate this quantity from theexperimental observations requires a knowledge of the collision number.6o J. C. McCoubrey, R. C. Milward, and A. R. Ubbelohde, Trans. Furday SOC.,1961, 57, 1472.61F.I. Tanczos, J . Chem. Phys., 1956, 25, 439.62 P. G. Dickens and A. Ripamonti, Trans. Faraday SOC., 1961, 57, 735.63 A. R. Blythe, T. L. Cottrell, and A. W. Read, Trans. Furaday SOC., 1961,57,935.64 R. C. A v e and S. Legvold, J . Chem. Phys., 1960, 33, 91.66 W. J. Wittaman, J . Chsm. Phys., 1961, 35, 1.66B. Widom, J . Chem. Phys., 1959, 30, 238.s7K. E. Shuler and R. Zwanzig, J . Chem. Phys., 1960, 33, 1778.68H. 0. Pritchard, J . Phys. Chem., 1961, 65, 504.34 GENERAL AND PHYSICAL CHEMISTRYThe method of calculating collision numbers in the two recent books 2, 3has been criticised as being too heavily weighted at low temperatures byattractive deflection^.^^Some examples, such asthat for nitric oxide, of energy transfer from higher, identified, states havebeen discussed above.Vibrational-energy transfer from excited statesmay be studied by the examination of fluorescence stabilisation in poly-atomic molecules. The methods involved in such studies were reviewed in1957,60 and furfher experimental results for aromatic systems have becomeavailable.61 The method has also been used for other types of compound,as, for example, in a study of the photochemistry of cyclopentanone.62Added gases did not show great differences in energy-transfer efficiency.Apparently abnormal rotational distributions of hydroxyl in detonationhave been observed 63 and attributed to rotational disequilibrium. Theobservations are now 64 attributed to turbulence. Indeed, it has beenshown 65 that the cross-section for rotational relaxation of hydroxyl inhydrogen-oxygen flames is even larger than the gas-kinetic collisional cross-section.Further related work on higher-energy states has been concerned withthe deactivation of excited radicals (see, for example, ref.66). This typeof investigation is, however, so closely related to chemical kinetics thatit is not considered further here.Energy transfer involving higher-energy states.T. L. C.4. INFRARED SPECTRA AND MOLECULAR INTERACTIONSCONSIDERABLE interest has been shown during the last few years in theefTect of molecular interactions on infrared spectra. This report reviewscertain aspects of the subject, vix., solvent egects, matrix spectra, and thespectra of adsorbed films.Most of the references are from publicationsduring the last four years but in certain cases earlier work is included.Since the last Annual Report, the I.U.P.A.C. Commission on spectro-scopy has published comprehensive sets of tables for the calibration ofgrating and of prism spectrometers. The continued publication of variouscard-index systems, such as that of D.M.S., has reduced the labour of locat-ing spectra, but the appearance of a Beilstein-type index of infrared spectra 2covering the years up to 1957 is an additional help.Intermolecular Forces and Solvent Eff ects.-Frequency shyk Consider-69 J. s. Rowlinson, MoZ. Phys., 1961, 4, 317.G O B . Stevens, Chem. Rev., 1957, 57, 439.61 B. Stevens, Discuss. Faraday SOC., 1959, 27, 34; Mol.Phys., 1960, 3, 589.s2R. Srinivasan, J . Amer. Chem. SOC., 1961, 83, 4348.63G. B. Kistiakowsky and F. D. Tabbutt, J . Chem. Phys., 1959, 30, 577.64 G. B. Kistiakowsky and R. K. Lyon, J . Chem. Phys., 1961, 35, 995.65T. Carrington, J . Chem. Phys., 1959, 31, 1418.66 R. E. Harrington, B. S. Rabinovitch, and M. R. Hoare, J . Chem. Phys., 1960,1 “ Tables of Wavenumbers for the Calibration of Infrared Spectrometers,”“ An Index of Published Infrared Spectra,” Ministry of Aviation, H.M.S.O.,33, 744.I.U.P.A.C., Butterworths Scientific Publns., London, 1961.London, 1960WILLIAMS : INFRARED SPECTRA 35able changes of both frequency andintensity occur in the vibrational spectrumof a molecule on going from the gaseous to the solution phase.One of thesimplest and earliest attempts to explain these effects was that of Kirk-wood 3 and of Bauer and Magat.4 This was based on the model of an oscil-lating point dipole in a spherical cavity in a continuous dielectric medium.The frequency of the oscillator was modified as a result of the field actingon it, owing to polarization induced in neighbouring molecules by its owncharge distribution. The treatment led to the well-known Kirkwood-Bauer-Magat (KBM) relation(1)where Av is the change in frequency on going from vapour to solution phase,Y is the vapour-phase frequency, E is the dielectric constant of the solvent,and C is a constant. The applicability and limitations of this model havesubsequently been examined in considerable detail by Pullin who appliedessentially the same treatment as Bauer and Magat and derived an equa-tion for a diatomic vibratorAV/V = C(E - 1)/(2& + I),AV/V = K - l ( l - A)-1[3f ‘ob,u0M‘/K + f ‘yB~OM’ + f ‘,,Mr2/2 + 3(f ’ 0 + f ’2v)PoJf”lY (2)where K and b are constants of the potential energy function, M’ and M“are the derivatives of the dipole moment ,uo-distance function, A and Bare functions of bond polarizability, and the quantities f‘ are constantsrelated to the reaction field of the dipole.The first and the third term inthis equation are equivalent to those given by Bauer and Magat and thesecond and fourth to those of West and Edwards.3 The equation wasextended to polyatomic molecules and approximate numerical calculationsshowed that the frequency shift, e.g., in vco, of acetone is about one-halfof that observed.Subsequently, P ~ l l i n 5 ~ showed that for acetone, fre-quencies varied linearly with the function(3)where n and E are the refractive index and the dielectric constant respectivelyof the solvent, B is a constant for each particular solute mode, and R is asolvent-dependent radius.BuckinghamJGQ using a model similar to Kirkwood’s, expanded thesolvent-solute interaction energy, U, as a power series in the normal co-ordinates of the solute and then treated the U and the anharmonic termsin the potential-energy function as small perturbations to the harmonicoscillator Hamiltonian. He found that for a diatomic molecule Av oc(U” - 3 U‘g/m,,) where U’ and U” are derivatives of the interaction energywith respect to the vibrational displacement and g/me is an anharmonicconstant.The theory indicated that Av/v should be independent of isotopic[(n2 - 1)/(2n2 + 1)RI + [B(& - + 1)W,J. G. Kirkwood, J . Chem. Phys., 1934, 2, 351; quoted by W. West and R. T.E. Bauer and M. Magat, J . Phys. Radium, 1938, 9, 319.SA. D. E. Pullin, Spectrochim. Acta, ( a ) 1958, 13, 125; ( b ) 1960, 16, 12; (c) Proc.A. D. Buckingham, Proc. Roy. SOC., (a) 1958, A , 248, 169; ( b ) 1960, A , 255, 32;Edwards, ibid., 1937, 5, 14.Roy. SOC., 1960, A, 255, 39.(c) Trans. Paraday SOC., 1960, 56, 75336 GENERAL AND PHYSICAL CHEMISTRYsubstitution and should be the same for both the fundamental and its over-tones. For non-polar solvents it was possible to write an equation(4)(5)A V l V = Cl + w 2 + C3)(& - 1)/W + I),AV/Y = C1 + C ~ ( E - 1)/(2& + 1) + C3(n2 - 1)/(2%2 + I),while for solvents with a dipolewhere Cl, C2, and C3 are constants depending on both solute and solvent.I n later papers@* extension to polyatomic molecules was considered, inaddition to the application of the method to intensities, band widths, andStokes and anti-Stokes Raman lines.A considerable number of publications on empirical approaches to theproblem of solvent shifts have appeared.Allen and Warhurst 7 showedthat AV/Y for the v1 symmetric mode of mercuric chloride, a Raman activefrequency, was a linear function of log E and that the slope of the plot fora number of solutes was a function of the bond ionic character.Grangeet aL8 have shown similarly that the relative frequency shifts (Av/v) for thehydrogen halides in carbon tetrachloride solution were a linear function ofthe Pauling electronegativity of the halogen atom.More recently, Le Fbvre 9 has put forward an empirical method of cal-culating solution frequencies based on equations which relate (i) bondpolarizability to the refractive index of the solvent and (ii) the frequencyin solution to the bond polarizability. Fair agreement is obtained betweenobserved and calculated values for acetone.The validity of the KBM equation has been tested by many workers.Bayliss, Cole, and Little 10 measured the frequencies? intensities, and half-band widths for C=O, C-H, and C-C bands in a range of solvents and foundthe equation inapplicable.Cannon and Stace l1 were unable to relate thehydroxyl shifts of ethanol and trifluoroethanol to the KBM equation.Other studies include those of the -CN,l2 >NH,13 -OH,14 and >CO l5 groups.Arbitrary classification of solvents into three groups has been made,based on their effect on either carbonyl groups l6 or acetylenic CH.l7Acetylenes have also been studied by Gastilovitch and his co-workers lSaand by Shuvalova . sb7 G. Allen and E. Warhurst, Trans. Paraday SOC., 1958, 54, 1786.P. Grange, J. Lascombe, and M. L. Josien, Spectrochim. Acta, 1960, 16, 981.9R. J. W. Le FBvre, Austral. J . Chem., 1961, 14, 312.ION. S. Bayliss, A. R. H. Cole, and L. H. Little, Austral. J . Chem., 1955, 8, 26.11 C.G. Cannon and B. C. Stace, Spectrochim. Acta, 1958, 13, 253.12 J. P. Jesson and H. W. Thompson, Spectrochim. Acta, 1958, 13, 217.l a R. E. Dodd and G. W. Stephenson, " Hydrogen Bonding," ed. D. Hadii andH. W. Thompson, Pergamon Press, London, 1959, p. 177; I. Suzuki, M. Tsuboi, andT. Shimanouchi, J . Chem. Phys., 1960, 32, 1263; K. B. Whetsel, W. E. Roberson,and M. W. Krell, Analyt. Chem., 1960, 32, 1281.14 Y. Sato, J . Chem. SOC. Japan, 1958, '79, 358; P. A. D. De Maine, L. H. Daly, andM. M. De Maine, Canad. J . Chem., 1960, 38, 1921.15L. B. Archibald and A. D. E. Pullin, Spectrochim. Acta, 1958, 12, 34.16 T. V. Yakovleva, A. G. Mmlennikova, and A. A. Petrov, Optics and Spectro-scopy, 1961, 10, 131.17B. Wojtkowiak and R.Romanet, Compt. rend., 1960, 250, 3980.18 (a) E. A. Gastilovich, D. N. Shigorin, E. P. Gracheva, I. A. Chekula, and M. F.Shostakovski, Optics and Spectroscopy, 1961, 10, 312; (b) E. V . Shuvalova, ibid., 1959,6, 452WILLIAMS : INFRARED SPECTRA 37Josien and her co-workers in particular have examined the KBMrelation, which was found to be satisfactory for XH vibrators only with afew non-polar solvents, e.g., carbon tetrachloride or n-hexane. Deviationfrom the equation was attributed to complex formation and this was con-firmed by the presence of two XH stretching bands in mixed solvents.Subsequently, equilibrium constants were determined.20 For example, theassociation constant for the equilibriumPyrrole + Solvent + Pyrrole, Solventlies in the range 0.23 l./mole for chlorobenzene to 2.7 l./mole for pyridine.A different approach has been employed by Bellamy and his co-workers,21who plotted Av/v for given XH vibrators in a series of solvents againstAv/v for a standard substance, e.g., v(NH) of pyrrole in the same series.This method eliminates the effect of the solvent, and straight lines wereobtained whose slopes were related approximately to the pK, value of theX-H bond.It was proposed that the frequency shifts were due to localassociation between the X-H dipole and a negative charge centre in aneighbouring solvent molecule. The lack of discontinuity in the plotsshowed that there was little difference in kind between association witha polar solvent, e.g., ether, and a non-polar solvent, e.g., carbon tetrachloride.This has however been disputed by Grange et aZ.8 I n a second paper 22ait was shown that >cO groups could be treated in the same fashion but sincethe dipole was >C=O the order of solvents along the plot was not the sameas for X-H solutes.The results were later extended 2Zb to groups of thetype -XO, where X = N, P, or S. In all these cases it was found thath / v for a series of solvents gave linear plots against AY/Y for a standard>CO compound, indicating that the mechanism of association with thesolvent was the same. Further, it was found23 that in a series of theacetyl derivatives of some N-heterocyclic compounds, the >CO solvent-sensitivity increased steadily in the order tetrazole, 1,2,4-triazole, imidazole,pyrrole, and pyrrolidine, which is also that of increasing CO dipole.Whenthe vibrating group is already associated 24 as in, e.g., carboxylic acid dimersor o-nitrophenol, local association with the solvent is nearly negligible andthe frequency is virtually solvent-insensitive. Mixed solvents studies, 24e.g., with pyrrole in carbon tetrachloride, benzene, and mesitylene, gave threebands a t frequencies corresponding to single-component solutions. Theill. L. Josien and N. Fuson, J . Chm. Phye., 1954, 22, 1169, 1264; M. L. Josienand J. Lascombe, Compt. rend., 1954, 238, 2414; M. L. Josien and G. Sourisseau, ibid.,1954, 238, 2525; M. L. Josien and J. Lascombe, J . Chim. phya., 1955, 52, 162; 1957,54, 761; M. L. Josien and P. Saumagne, Bull.SOC. chim. France, 1956, 937; 1958, 813;M. L. Josien, J. P. Leicknam, and N. Fuson, &id., 1958, 188.*ON. Fuson, P. Pineau, and M. L. Josien, J . Chim. phya., 1958, 55, 454, 464;“ Hydrogen Bonding,” ed. D. Hadii and H. W. Thompson, Pergamon Press, London,21 L. J. Bellamy, Spectrochim. Acta, 1959, 14, 192; L. J. Bellamy, H. E. Hallam,and R. L. Williams, Trana. Paraday SOC., 1958, 54, 1120.22 (a) L. J. Bellamy and R. L. Williams, Trans. Faraday SOC., 1959, 55, 14; ( b ) L. J.Bellamy, C. P. Conduit, R. J. Pace, and R. L. Williams, ibid., p. 1677.2a L. J. 13ellamy and R. L. Williams, Proc. Roy. Soc., 1960, A , 255, 22.24 L. J. Bellamy and H. E. Hallam, Tram?. Faraday SOC., 1959, 55, 220.8 - 8+6+ 6-6- 6 l1959, p. 16938 GENERAL AND PHYSICAL CHEMISTRYrelative areas of the three bands depended on the proportions of solvents,even though the overall dielectric constant remained constant.The effectof the shape of the solute molecule 25a and the solvent molecule 25b onsolvent-sensitivity has been studied with substituted phenols and ethers,respectively. Similar solvent plots to those mentioned above have beenreported for -CN,26ur >NH, and -OH groups.26c An attempt hasalso been made to use them to measure the basicity of aromatic compounds,correlations being observed between Av/v for a standard XH compoundand such variables as the heat of mixing of chloroform with the solvent,the lowering of vapour pressure, and ionization p0tential.27~ A similarcorrelation between heat of mixing with chloroform and the shift of theOD frequency in CH,*OD in cyclic sulphoxides and ketones27b has beenreported .Coulson 28 has considered theoretically the reasons for the breakdownof the dielectric-constant approach and for the applicability of a local-interaction model.Attempts to predict frequency shifts on the basis ofsuch a model have been made in a number of cases. La Lau 29 calculatedthe change in the CH bending force constant of benzene, assuming electro-static interaction between a positive charge on the hydrogen and a negativecharge on a solvent such as acetone or acetonitrile, comparatively goodagreement being obtained between observed and calculated Av/v values.Drickamer and his co-workers 3O examined the shifts in frequency resultingfrom the application of high pressures to solutions.They interpreted theirresults in terms of the interaction of the vibrator with each bond of thesolvent, the relative contribution from dispersion, orientation, induction,and repulsion forces being estimated from the formuheidisp. = -~ITiaai/[(l + Ii)RF]; etepuls- = Ci/Ri12;where e is the energy of interaction, I ionization potential, a bond polariz-ability, p bond dipole, R the solute-solvent distance, f an orientationfactor, and C a constant. On this basis they found that for >C=O incarbon disulphide the inductive interaction constituted 65% of that observed.Some cases, for which the shift of band position with pressure is claimed toobey the KBM relation, are probably of this type.31A calculation similar to that above has been made by Linevsky 32 for25 (a) L.J. Bellamy and R. L. Williams, Proc. Roy. Soc., 1960, A, 254, 119; (b) L. J.Bellamy, G. Eglington, and J. F. Morman, J., 1961, 4762.(a) H. W. ThompsonandD. J. Jewell, Spectrochim. Ackc, 1958, 13, 254; (b) N. S.Bayliss, A. R. H. Cole, and L. H. Little, ibid., 1959, 15, 12; (c) W. C. Price, W. F. Sher-man, and G. Wilkinson, Proc. Roy SOC., 1960, A , 255, 5.27 (a) M. L. Josien and G. Sowisseau, " Hydrogen Bonding," ed. D. Hadii andH. W. Thompson, Pergamon Press, London, 1959, p. 129; ( 6 ) M. Tamres and S. Seaxles,J . Amer. Chem. SOC., 1959, 81, 2100.2sC. A. Coulson, PTOC. Roy. SOC., 1960, A , 255, 69.29 C. La Lau, Spectrochim. Acta, 1959, 14, 181.3O E.Fishman and H. G. Drickamer, J. Chem. Phys., 1956,24, 548; A. Benson andH. G. Drickamer, ibid., 1957, 2'4, 1164; R. R. Wiederkehr and H. G. Drickamer, ibid.,1958, 28, 311.31 M. L. Josien and P. Dizabo, Compt. rend., 1956, 243, 44; M. L. Josien, J. Las-combe, and N. Fuson, J. Chem. Phys., 1956, 25, 1291.32M. J. Linevsky, J. Chem. Phys., 1961, 34, 587.} (6) eielectrostat. = ,,upi fi2/Ri3; eind. = p2ai fi3/Ri6WILLIAMS : INFRARED SPECTRA 39lithium fluoride in matrices of solid argon, krypton, xenon, or nitrogen.For the first three matrices, the component of the interaction energy due toinduction was calculated from the formula (7):(7) einduct. - - [ap2(3 cos20 + 1)/2r6],from which the frequency shift was found to be -45 cm.-l, leaving a furthershift of 20-30 cm.-1 due to dispersion forces. In the case of nitrogen, therewas also a dipole-quadrupole interaction of -55 cm.-l, which in con-junction with an induction shift of 40 cm.-l left a component of -30 crn.-lto dispersion.Calculations on the basis of an intermolecular interaction with a 6-9potential function have been made for MX,-type molecules by H e i ~ k l e n , ~ ~to determine the frequency changes which occur on going from a gaseousto a condensed phase. A similar method has been applied satisfactorily tothe vibrational structure of the electronic bands of the NH radical in argon,krypton, or xenon matrices, observed in the ultraviolet region.34 Galatryand Schuller 35a have considered a KBM-type model but with the oscillatingdipole inducing a dipole in each of the surrounding molecules, while Schuller,Galatry, and Vodar 35b have calculated the effect of dispersion on hydrogenchloride dissolved in carbon tetrachloride or benzene, by using a Heitler-London wave function with an ionic term.They derived an equationAv/v = - [e2/2nv2m][n~(4g + 7f)]/Bo3,where e is the electronic charge, m is the reduced mass of the oscillator, a isthe polarizability of the solvent, y is the mechanical anharmonicity, R, theminimum distance of approach of the solute and solvent, n = iV/V is thenumerical density of the solvent, and g andf are quantities calculable fromthe wave equation. Insertion of numerical quantities in expression (6)showed that dispersion could account for 30--50% of the observed shift,while induction amounted to only 2-5--5%.Another model for the calculation of frequency shifts has been suggestedby Person and his co-w0rkers,~6 who studied the complexes between varioushalogen compounds, e.g., iodine chloride, iodine cyanide, chlorine, andbromine, and donor solvents.Intensities, frequencies, and half-bandwidths were measured and the changes were interpreted on the basis ofMulliken’s charge-transfer theory. It is possible to write the structure of thecomplex in terms of resonance between D-n-X-Y (no bond) and D +--(X-Y) -.Person estimated the charge transferred in this process, E,, from the inten-sity of the infrared bands of the various halogen compounds in solution andshowed that it gave linear plots against Ak/k, the relative change in forceconstant for the vibration in question.The magnitude of Ak/E (w2Av/v,33 J. Heicklen, Spectrochim. Acta, 1961, 17, 82.34 M. McCarty and G. W. Robinson, J . Amer. Chem. SOC., 1959, 81, 4472.35 (a) L. Galatry and F. Schuller, Compt. rend., 1957, 244, 1749; 1957, 245, 901;( b ) F. Schuller, L. Galatry, and B. Vodar, Spectrochim. Acta, 1960, 16, 789.s6 W. B. Person, R. E. Humphrey, W. A. Deakin, and A. I. Popov, J . Amer.Chem. SOC., 1958, 80, 2049; W. B. Person, R. E. Humphrey, and A. I. Popov, ibid.,1959, 81, 273; W. B. Person, R. E. Erickson, and R. E. Buckles, ibid., 1960, 82, 29;also D. C. Cook, J . Amer. Chern. SOC., 1958, 80, 4940 GENERAL AND PHYSICAL CHEMISTRYfor small changes) depends on the donor strength of D and on the acceptorstrength of the bond X-Y.For a given pair of solutes the difference inacceptor strength is constant so that the plot of Av/v for one acceptor in aseries of solvents against Av/v for a second acceptor should give a straightline, as observed by Bellamy et aL21Successful attempts have been made by Caldow and Thompson 37 tomodify the Buckingham equations (4) and ( 5 ) . They observed that theCH frequency of hydrogen cyanide or phenylacetylene dissolved in solventsof the type RCN, RCl, and R*CO*CH, was a linear function of the Taftinductive factor o* for the residue R. A term C 4 ~ * was therefore added toequations (4) and (5). A set of constants C,, C2, C3, C4 was chosen to givethe best fit between calculated and observed frequency displacements fora given solute in eight selected solvents and was then used to predict thedisplacements for other solvents.Excellent agreement was obtained.Moreover, it was observed that for the CH shifts of hydrogen cyanide theC40* term was dominant, as would be expected for the local associationmodel of Bellamy et aL21 On the other hand, for a number of carbonyl-containing solutes, the dielectric constant terms, involving C, and C3, weresubstantial. A similar result has been obtained for C-C1 bonds by Hallamand Ray.38 It is noteworthy how these conclusions agree with the magni-tude of the dielectric contribution obtained by Pullin 5a and by Drickamer’sschool 3O for the carbonyl group and by Schuller’s school 35 for hydrogenchloride.Caldow and Thompson 37 also examined the effect of isotopicsubstitution on the solvent shift of the CH band of hydrogen cyanide.They found thatHuong et ~ 1 . 3 9 ~ have, however, shown more recently that this is fortuitousand that the relation (10) holds:(AV/Y2)H-CN = (AY/Y2)D-CN. (9)(Av/y)Hc + (A~/Y)Hc=N = (AV/Y)DC + (AY/Y)DC=N. (10)I n a number of cases 3ga3 constancy of Av/v with isotopic substitution wasfound, as predicted by Buckingham.6Though solvent shifts of infrared bands are not often related to thoseof ultraviolet bands, Ito et ~ 1 . ~ 0 ~ have shown that, for ketones, ( A Y / Y ) ~ ~ forthe infrared bands gives linear plots against a similar function for then-n* transition. This is attributed to solute-solvent association in theground state only, since on n-n* excitation the dipole of the carbonyl groupbecomes very small.Becker 40b has similarly interpreted the behaviour ofbemophenone in various solvents.Application of solvent eflects. Solvent effects have been used extensivelyfor diagnostic purposes, Thus the Av/v values for a band should give linear37 G. L. Caldow and H. W. Thompson, Proc. Roy. SOC., 1960, A, 254, 1.3*H. E. Hallam and T. C. Ray, Nature, 1961, 189, 915.39 ( a ) P. V. Huong, J. Lascombe, and M. L. Josien, J . C h h phys., 1961,58, 694;( b ) J. P. Leicknam, J. Lascornbe, N. Fuson, and M. L. Josien, BUZZ. SOC. chim. France,1959, 1516; ( c ) M. L. Josien, J. Lascombe, and J. P. Leicknam, Compt. rend., 1958,246,401418.(a) M.Ito, K. Inuzuka, and S. Imanishi, J . Amer. Chem. Soc., 1960, 82, 1317;( b ) R. S. Becker, J . Mol. Spectroscopy, 1959, 3, 1WILLIAMS : INFRARED SPECTRA 41plots against those of a standard band, e.g., v(C0) of acetophenone, only ifthe band arises from a dipole similar in structure to the standard. Thishas been used to show that one component of CO doublets in ethylenecarbonate 27a and in cyclopentanone 41 results from Fermi resonance of acombination band with the fundamental, while in a series of esters of thetype R*N(N02)*C0,Et 42 it is the result of rotational isomerism.Carbonyl assignments based on solvent shifts have been made in salicyl-aldehydes, 43a arylazonaphthols, 43b pyridones, 43c* and pyrones, 43a andsimilar methods have been used for the thiocarbonyl group >C=S in a rangeof compounds 44a* and for the C-0 band of secondary alkylcyclohexanols.45Conversely, lack of solvent-sensitivity of the hydroxyl band in certain ortho-substituted phenols has been taken to indicate intermolecular b~nding.~GChangeof solvent usually alters the ratio of isomers and it is possible to makedeductions on the conformation of the isomer from the nature of the solvent.Substances examined include a-chloro-ketone~,~7~ a-chloro- and a-bromo-cyclohe~anones,~~~~ a-bromocyclo-octanone,47d 2,3-dihalogenopropene~,~7~dimetkyl phosphonate,22b and alkyl nitrites.22b Other studies involvingsolvent effects include those on acetylenes,48 nitroanilines,49 a~iline,~o car-bony1 cornpounds,51~ 52 hydrogen sulphide and hydrogen deuterium sul-~ h i d e , ~ 3 the deuterium compound being used to olarify the assignment ofthe v1 and v3 stretching frequencies.Inorganic investigations by thismethod include the nature of the metal-carbonyl link in metal ~arbonyls,~~and the metal-hydrogen stretching frequency in some complex platinumand iridium hydrides .Intensity changes. The effects of solvents on band intensities have notbeen examined so extensively as those on frequencies. Earlier referencesmay be found in a review by Browq56 in Annual Reports by Mills,57 andRotational isomerism has been studied in a number of cases.41 G. Allen, P. S. Ellington, and G. D. Meakins, J., 1960, 1909.4zE. H. White and D. W. Grisley, J. Amer. Chem. SOC., 1961, 83, 1191.43 (a) C.J. W. Brooks and J. F. Morman, J., 1961, 3372; (b) K. J. Morgan, J., 1961,2151; ( c ) L. J. Bellamy and P. E. Rogasch, Spectrochim. Acta, 1960, 16, 30; (d) A. R.Katritzky and R. A. Jones, J., 1960, 2947; ( e ) A. R. Katritzky and R. A. Jones, Spectro-c h i m Acta, 1961, 17, 64.(a) L. J. Bellamy and P. E. Rogasch, J., 1960, 2218; (b) L. H. Little, G. W. Poling,and J. Leja, Canad. J. Chern., 1961, 39, 1783.45 G. Chiurdoglu and W. Masschelein, Bull. SOC. chim. belges, 1961, 70, 307.46 J. H. Richards and S. Walker, Trans. Paraday Soc., 1961, 57, 399, 412.47 (a) L. J. Bellamy and R. L. Williams, J., 1957, 4294; (b) J. Allinger and N. L.Allinger, Tetrahedron, 1958, 2, 64; N. L. Allinger and J. Allinger, J. Amer. Chem. SOC.,1958, 80, 5476; (c) K.Kozima and Y. Yamanouchi, ibid., 1959, 81, 4159; ( d ) J. Allingerand N. L. Allmger, ;bid., p. 6736; ( e ) E. B. Whipple, J . Chem. Phyls., 1961, 35, 1039.* 8 J. C. D. Brand, G. Eglington, and J. F. Morman, J., 1960, 2526; R. West andC. S. Kraihanzel, J. Amer. Chem. SOC., 1961, 83, 765.4gL. K. Dyall, Spectrochim. Acta, 1961, 17, 291.50A. G. Moritz, Spectrochim. Acta, 1961, 17, 365.51 K. Inuzuka, M. Ito, and S. Imanishi, Bull. Chem. SOC. Japan, 1961, 34, 467.5z T. V. Yakovleva, A. G. Maslennikova, and A. A. Petrov, Optics and Spectroscopy,53P. Saumagne, J. Lascornbe, and J. Devaure, Conapt. rend., 1961, 253, 632.55D. M. Adams, Proc. Chem. SOC., 1961, 431.66T. L. Brown, Chem. Rev., 1958, 58, 681.67 I. M. Mills, Ann. Reports, 1958, 55, 65.1961, 10, 64.C.Barraclough, J. Lewis, and R. S. Kyholm, J., 1961, 258242 GENERAL AND PHYSICAL CHEMISTRYin a paper by Buckingham.6a I n the last, Buckingham showed that, onthe basis of the dielectric model, band intensities were proportional to afactor involving the refractive index, n, of the solvent and the rate of changeof dipole with normal co-ordinate of the solute in association with its nearestneighbours. For the transition 0 --+ n, (A,)o+Jv(n+l), where A, is theband intensity of the solution, should be constant. In the later papers,6b~cexpression (1 1) was derived :and a number of isotopic substitution relations were also proposed, e.g.,( A , / Y ~ ) is constant; At2/v2 is constant where A, is the half-band width.Caldow et al.58 have shown that equation (11) holds quite well for aceto-nitrile or trichloroacetonitrile, but that it is not satisfactory for hydrogencyanide or deuterium cyanide.Similarly, isotopic substitution constanciesfor (A,/vn) and A$2/v2 were found to be obeyed. In many cases it waspossible to plot &/A, for one solute in a series of solvents against ASIA, fora second solute in the same solvents. A, could also be plotted against theTaft o* factor for the solvent in some instances.Forel, Leicknam, and Josien 59 have shown that, for the CH band ofchloroform, A,/$ is constant. Studies have also been made on the anti-symmetric and symmetric modes of methylene chloride 6o and on the C-Imode of methyl iodide 61 in different solvents.Studies of a number of substances dissolved inrelatively inert solvents such as carbon tetrachloride or stannic chloridehave shown that a considerable degree of rotational freedom is retained.The evidence for rotation is based on band contour.With diatomic mole-cules, e.g., hydrogen halides, carbon monoxide, nitric oxide, and also withammonia and methane, the band is of the same width as that in the gas butwith a strong central maximum and sub-maxima corresponding to P and Rbranch maxima of the gas spectrum.62 The occurrence of the central Qbranch has been explained theoretically by Galatry. 63 For symmetric-topmolecules, e.g., methyl halides, Jones and Sheppard 64@ found that the A,-class bands were sharp and could be fitted by a Lorentz function whereasthe E-class bands varied considerably in width and could not be fitted bythis function.Moreover, the band widths of the latter gave linear plotsagainst the corresponding &-branch separations in the vapour state, indi-cating clearly that there was rotation about the %fold symmetry axis insolution. This work has been extended to the internal rotation of methylRotation in solution.68 G. L. Caldow, D. Cunliffe-Jones, and H. W. Thompson, Proc. Roy. SOC., 1960,59 M. T. Forel, J. 9. Leicknam, and M. L. Josien, J. Chim. phys., 1960, 57, 1103.6oM. L. Josien, N. Fuson, and A. Lafaix, Compt. rend., 1959, 249, 256.6a J. Lascombe, P. V. Huong, and M. L. Josien, Bull. Sac. chim. France, 1959,1175; M. 0. Bulanin and N. D. Orlova, Optics and Spectroscopy, 1958, 4, 569; C.G.Cannon, Spectrochim. Acta, 1958, 10, 425.63 L. Galatry, Spectrochim. Acta, 1959, 15, 849.64 ( a ) W. J. Jones and N. Sheppard, Trans. Faraday SOC., 1960, 56, 625; (b) Proc.Chm. SOC., 1961, 420.A, 254, 17.L. Angell, Spectrochim. Acta, 1961, 17, 1118WILLIAMS : INFRARED SPECTRA 43groups.6@ Partial resolution of fine structure of thiocyanic acid in solutionhas also been observed.65Matrix Studies.-Many applications of the matrix isolation technique ofPimentel and his co-workers have been made. In this method a substanceis mixed in the vapour phase with a large excess of an inert diluent, e.g.,argon, and then condensed on to a transparent plate held a t low tem-peratures.66Studies have included hydrogen bonding in water 67a and in methanol,67bfree rotation of ammonia 6Ba and water in the matrix, the non-forma-tion of carbonic acid from water and carbon and carbon mon-0xide.70~~ In the last,'Oa the invariance of Av/v for isotopic substitution,predicted by Buckingham,6 was checked.The considerable sharpening of bands which occurs on matrix formationhas been used to resolve nearly coincident vibrations in carbonyl chloride,71Qdisiloxane,71b and monomeric 71' and dimeric 71d formic acid.The most important application of the method, however, is in the studyof species which are unstable under normal conditions. Fateley and hisco-~orkers,~z for example, examined the oxides of nitrogen a t low tempera-ture and found that nitric oxide existed not only as a monomer but also ascis- and trans-dimers; that nitrogen dioxide occurred as monomer and twodimers, ONO-NO, and possibly 02N-N02 ; and dinitrogen trioxide occurredas ON-NO, and as ONONO.Photolysis of hydrazoic acid in a matrix hasbeen shown to give intermediates which are believed to be NH 73a or NH,,7*while photolysis of hydrazoic acid-oxygen mixtures has yielded cis- andtrans-isomers of nitrous acid. 73c* Other photochemical reactions whichhave been studied, include: CH3*NO2 or CK3*ON0 --+ HN0;72 CH,N2 -+CH, ; 7 5 HI- or HBr-CO -+ HCO ; 76 CH,*N3 --+ CH,:NH ; 77 decompositionof CfiT3;78 and proton abstraction by CH, generated from CH,I.79 The66N. Legge and A. D. E. Pullin, Proc. Chem. SOC., 1961, 342.66G. C. Pimentsl, D. A. DOWS, and E. Whittle, J .Chem. Phys., 1954, 22, 1943;E. D. Becker and G. C. Phentel, ibid., 1956, 25, 224; G. C. Pimentel, Spectrochim.Acta, 1958, 12, 94.6 7 (a) M. Van Thiel, E. D. Beckor, and G. C. Pimentel, J . Chem. Phys., 1957, 27,486; ( b ) M. Van Thiel, E. D. Becker, and G. C. Pimentel, ibid., p. 95.g8 (a) D. E. Milligan, R. M. Hexter, and K. Dressler, J. Chem. Phys., 1961, 34,1009; ( b ) E. Catalano and D. E. Milligan, ibid., 1959, 30, 45; (c) J. A. Glasel, ibid.,1960, 33, 252.'j9M. E. Jacox and D. E. Milligan, Spectrochim. Acta, 1961, 1'4, 1108.7 0 (a) G. E. Ewing and G. C. Pimentel, J. Ckm. Phys., 1961, 35, 925; ( b ) A. G.Maki, ibid., p. 931.71 ( a ) E. Catalano and K. S. Pitzer, J . Amer. Chem. SOC., 1958, 80, 1054; ( b ) R. F.Curl and K. S. Pitzer, ibid., p.2371; (c) R. C. Millikan and K. S. Pitzer, ibid., p. 3515;( d ) T. Miyazawa and K. S. Pitzer, J . Chem. Phys., 1959, 30, 1076.W. G. Fateley, H. A. Bent, and B. L. Crawford, J . Chem. Phys., 1959, 31, 204.7s (a) E. D. Becker, G. C. Pimentel, and M. Van Thiel, J. Chem. Phys., 1967, 26,145; (b) M. Van Thiel and G. C. Pimentel, ibid., 1960, 32, 133; (c) J. D. Baldeschwielerand G. C. Pimentel, ibid., p. 1008; ( d ) Q. C. Pimentel, J . Amer. Chem. SOC., 1958,80, 62.74H. W. Brown and G. C. Pimentel, J. Chem. Phys., 1958, 29, 883.76 D. E. Milligan and G. C. Pimentel, J . Chem. Phys., 1958, 29, 1405; T. D. Gold-farb and G. C. Pimentel, ibid., 1960, 33, 105; J . Amer. Chem. SOC., 1960, 82, 1865.76 G. E. Ewing, W. E. Thompson, and G. C. Pimentel, J .Chem. Phys., 1960, 32,927.77D. E. Milligan, J . Chem. Phys., 1961, 3!5, 1491.7BC. D. Bass and G. C. Pimentel, J . Amer. Chern. SOC., 1961, 83, 3764.E. Milligan, J . Chem. Phys., 1961, 35, 37244 GEENEBAL AND PHYSICAL CHEMISTRYmathematical theory of free-radical stabilization in matrices has been con-sidered by Golden.80Studies have also been made on polyatomic anions in matrices preparedby compressing powdered mixtures of a salt containing such an anion withthe corresponding alkali halide. Considerable frequency changes take place,depending on the nature of the alkali halide. Maki and Decius 81 examinedthe CNO- ion in this way, and found that the observed frequency changeswere very much greater than those calculated on the basis of dipole-induceddipole interactions.Repulsion forces made a much more important con-tribution. Ketelaar et aL8, showed that for NO,- in alkali halides, the plotof the antisymmetric Y(NO) frequency against the reciprocal of the latticedimension gave a series of parallel lines, corresponding to the different alkali-metal halides. Subsequently, 83 by applying a KBM-type correction, theywere able to reduce the plots to a single line. More recently, however,Strasheim and Buijs84 showed that the frequencies of all vibrations ofNCO-, NO,-, BH,-, and HF,- gave linear plots against the sum of therepulsive, dipole-dipole, and dipole-quadrupole interactions of the alkali-halide lattice, as determined by the Born-Mayer equation. In addition,they stated that the major part of this lattice contribution arises from short-range repulsive forces.A very comprehensive study of ions in alkali-halide lattices has beenreported by Price, Sherman, and Wilkins~n,~~* 26c covering a range of tem-peratures ; high resolution was used and variation of frequencies, intensities,and contour were investigated.A number of Buckingham’s predictions 6were verified and an extension of the equation Av,, JvTn, = constant toexpression (12) was shown to hold.(12) A(~,Y, + ~ 2 ~ 2 + ~ 3 ~ 3 ) = v,Avl + ~ J Y , + v3Av3.Adsorbed Molecules.-The infrared spectra of molecules physically orchemically adsorbed on surfaces such as porous glass, silica, or alumina oron metallic films supported by these substances have provided valuableinformation both on the mechanism of adsorption and on catalysis.Thesubject up to 1958 has been comprehensively reviewed by Eischens andPliskin.86 More recent work has been discussed by Sheppard *’ and byYates.88The rotational freedom of methyl bromide adsorbed on porous glass hasbeen studied by Sheppard et ~ 1 . 8 ~ who used the band contours in a similarway to that used for rotation in solution.64 The surface hydroxyl groupsof porous silicates 90a and y-alumina 90b have been examined, particularly8 0 s . Golden, J . Chem. Phys., 1958, 29, 61.81A. Maki and J. C. Decius, J . Chem. Phys., 1958, 28, 1003; 1959, 31, 772.82 J. A. A. Kehlaar. C. J. H. Schutte, and B. L. Schram, Spectrochim. Acta, 1959,The latter author, however, reviews only physical adsorption.- -13, 336.88 J.A. A. Ketelaar and J. van der Elsken, J . Chem. Phys., 1959, 30. 336. - -84A. Strasheim and K. Buijs, J . Chem. Phys., 1961, 34,-691.85 W. C. Price, W. F. Sherman, and G. R. Wilkinson, Xpectrochim. Ada, 1960,8sR. P. Eischens and W. A. Pliskin, Adv. Catalysis, 1958, 10, 1.87N. Sheppard, Spectrochim. Acta, 1959, 14, 249.88D. J. C. Yates, Adv. Catalysis, 1960, 12, 265.89 N. Sheppard, M. V. Mathieu, and D. J. C. Yates, 2. Elektrochem., 1960, 64, 734.90“() A. Terenin and V. Filimonov, “Hydrogen Bonding,” ed. D. Hrtdii and16, 663WILLIAMS : I N F R A R E D SPECTRA 45with reference to hydroxyl-frequency shifts which occur when other sub-stances are adsorbed on the surface. Such frequency shifts have beenshown by Bellamy and Williams 23 to give linear plots against (AY/Y) for theNH frequency of pyrrole dissolved in these substances, indicating the closesimilarity in mechanism between surface adsorption and local interactionin solution.The physical adsorption of water on synthetic zeolites 91a andon silica gel 91b has also been examined, and Little 92 has used the break-down of selection rules on physical adsorption to show that the infraredinactive v5 of ethylene occurs at 3070 cm.-l.The chemical adsorption of acetylene and ethylene on silica-supportedpalladium or copper has been investigated by Little, Sheppard, and Yates 93who showed from the CH stretching frequencies that, initially, acetylenegave olefhic CH bands while ethylene gave similar bands but with somesaturated CH absorptions in addition.On hydrogenation, Me[ CH,],*CH,type spectra appeared where ?z > 3. Yates and Lucchesi 94 have shown thatacetylene and methylacetylene are strongly adsorbed on alumina, with themolecules perpendicular to the surface, while dimethylacetylene is heldparallel to the surface. Isomeric butenes, on adsorption on porous glass,give the same species.95Several investigations of carbon monoxide chemisorption have beenreported, including that on 1lletals,~6 and the effect of poisoning on theadsorption on nickeL97 Yates and O'Neill have examined the effect of thesupport; on the spectrum of adsorbed carbon monoxide on both nickelQs"and nickel oxide.9* In the latter study, nickel oxide on alumina was foundto hold carbon monoxide as a carbonate complex, but nickel oxide on titaniabound it as 40,-.Silica-supported oxide did not react, but C0,- groupswere formed when oxygen was subsequently admitted. Similar resultshave been found for both carbon monoxide and carbon dioxide adsorbed onanatase and rutile 99 and on zinc oxide.loOOther spectroscopic studies of adsorption include that of formic acidon various surfaces;lol nitric oxide on transition metals, salts, and oxides;102H. W. Thompson, Pergamon Press, London, 1959, p. 545; ( b ) J. B. Peri and R. B.Hannan, J . Phys. Chew., 1960, 64, 1526.91 (a) H. A. Szymanski, D. N. Stamires, and G. R. Lynch, J . Opt. SOC. Avr$er.,1960, 50, 1323; ( b ) A. V. Kiselev and V. I. Lygin, Kolloid.Zhur., 1960, 22, 403.9nL. H. Little, J . Chem. Phys., 1961, 34, 342.98 L. H. Little, N. Sheppard, and D. J. C. Yates, Proc. Roy. SOC., 1960, A , 259,04D. J. C. Yates and P. J. Lucchesi, J . Chem. Phys., 1961, 35, 243.06L. H. Little, H. E. Klauser, and C. H. Amberg, Canad. J . Chem., 1961, 39, 42.e6R. A. Gardner and R. H. Petrucci, J . Amer. Chem. SOC., 1960, 82, 5051.B7 J. T. Yatss and C. W. Garland, J . Phys. Chem., 1961, 65, 617; C. W. Garland,ibid., 1959, 63, 1423.C. E. O'Neill and D. J. C. Yates, (a) J . Phys. Cltem., 1961,65, 901 ; (b) Spectrochiin.Acta, 1961, 17, 953.loo S. Matsushita and T. Nakata, J . Chem. Phys., 1960, 32, 983; J, H. Taylor andC. H. Amberg, Canad. J . Chem., 1961, 39, 535.lol J. Fahrenfort and H. F. Hazebroek, 2.phys. Chem. (Frankjwt), 1969, 20, 105;I(. Hirots, K. Kuwata, and S. Asai, J . Chem. SOC. Japan, 1959, 80, 701; K. Shindo,Y. Nakai, K. Fueki, K. Hirota, and T. Otaki, {bid., p. 1215; J. K. A. Clarke and A. D. E.Pullin, Trans. Paraday SOC., 1960, 56, 534.242.O9D. J. C . Yaks, J . Phys. Chem., 1961, 85, 746.'1oZA. N. Terenin and L. M. Row, Spectrochim. Acta, 1959, 15, 94646 GENERAL AND PHYSICAL CHEMISTRYnitrobenzene on silica;lo3 hydrogen and deuterium on platinum ;lo4 am-monia,106a and the reaction of ammonia lo5* with carbon disulphide onalumina; alcohols on chromic oxide;lo6 methanol and phenol on micro-porous glass;l07 and the spectra of monola,yers on metal mirrors.108R. L. W.5. CHEMICAL REACTIONS STUDIED BY USING SHOCK TUBESA REVIEW on the use of shock tubes has been given recently by Pritchard.1The present Report is concerned with papers published in 1960 and 1961,but it does not consider the use of shock tubes to study gas flows or high-temperature plasmas.Developments in Shock Techniques.-Some reactions can be studied byusing a shock tube to heat reactants for a certain time which is followed bycooling and analysis of the products.A simple shock tube has been usedby Greene et aZ.,2 while the chemical shock tube has been developed byGlick et aZ.3 Alternatively, the reaction can be followed directly in theshock-heated gas. Using the chemical shock tube Boudart and his co-workers have made allowances for the fact that all parts of the gas samplewhich is analysed are not heated for the same time.4 However, most ofthe recent developments have been connected with the second method.Thus the improvement in fast infrared detectors has enabled vibrationalrelaxation times to be compared by using infrared as well as ultravioletmethods.5 The use of absorption spectroscopy has been extended into thevacuum ultraviolet region, which gives an especially sensitive method ofmeasuring the concentration of oxygen.6 For studying reactions at lowdensities DUE has used an electron-beam densitometer.Gaydon andHurle 8 and Bauer et aL8 have extended the method of following a reactionby measuring the change in temperature by a reversal technique by usingchromium lines.8 It cannot be used successfully with monatomic gases, oroxygen, but otherwise is generally applicable.103M.Okuda, J . Chem. SOC. Japan, 1961, 82, 1121.l’J4W. A. Pliskin and R. P. Eischens, 2. phys. Chem. (Fmnkfurt), 1960, 24, 11.lo5 ( a ) D. E. Nicholson, Nature, 1960, 186, 630; ( b ) E. H. Parry and H. Rubalcava,106 L. M. Roev and A. N. Terenin, Doklady Akad. Nauk S.S.S.R., 1959,124, 373.10’ A. M. Bogomolny and Yu. A. Lyubimov, Optics and Spectroscopy, 1960, 8, 131.1 0 8 s . A. Francis and A. H. Ellison, J . Opt. SOC. Amer., 1959, 49, 131.1 H. 0. Pritchard, Quart. Rev., 1960, 14, 46.2E. F. Greene, R. L. Taylor, and W. L. Patterson, jun., J . Phys. Chem., 1958,8 H. S. Glick, W. Squire, and A. Hertzberg, “ Fifth Symposium (International)H. S. Glick, J. J. Klein, and W.4V. Kevorkian, C. E. Heath, and M.Boudart, J . Phys. Chem., 1960, 64, 964.SF. Robben, P. R. Manson, and J. J. Allport, J . Chem. Phys., 1960, 33, 630.6M. Camac, J . Chem. Phys., 1961, 34, 448; S. A. Losev, DokWy Akad. NaukS.S.S.R., 1958, 120, 1291. R. W. Patch, United Aircraft Co., Res. Lab. Res. Rept.No. R 1558-1 (Sept. 1961); 0. L. Anderson, United Aircraft Co. Res. Lab. Res. Rept.7R. E. Duff, Phys. Fluids, 1959, 2, 207.8A. G. Gaydon and I. R. Hurle, Proc. Roy. SOC., 1961, A , 262, 38; S. H. Bauer,J . Phys. Chem., 1960, 64, 955.62, 238.on Combustion,” Reinhold Publ. Corp., New York.Squire, J . Chem. Phys., 1957, 27, 850.NO. R 1828-1 (Aug. 1961).J. H. Kiefer, and B. E. Loader, Canad. J . Phys., 1961, 39, 1113SIMPSON: REACTIONS STUDIED USING SHOCK TUBES 47A general technique for following reactions has been developed byBradley and Kistiakowsky ; this uses a time-of-flight mass spectrometer tofollow the concentrations of species produced by a shock wave.9 Thespectrometer has a time resolution of 50 psec., which is not as good as thatavailable with an optical absorption method when that can be used, but itis not a specific method and it can follow several species simultaneously.These are considerable advantages as the concentration of species such asoxygen atoms cannot be followed readily by other means and it is diEcultto follow several species simultaneously in the short time available in shock-tube experiments, However, there are difEculties such as the possibility ofsome of the sample gas coming from the boundary layer, which is a regionof cool gas spreading from the tube walls into the heated gas after the shockwave has passed.Furthermore, in the present arrangement there is someuncertainty as to the temperature of the reactants owing to the considerableattenuation of the incident shock wave, and in general temperatures behindreflected shock waves are less well known than those behind incident shockwaves though this effect is minimized by using a mixture diluted with aninert gas.In studying kinetics by a shock-tube method, small errors in the shockspeed can lead to errors in the calculated temperatures which have an impor-tant effect in determining rate constants. This means that shock speedshave to be measured very accurately and estimates made as to when shockattenuation and the growth of boundary layers will contribute errors tothe measurements.1° There is more uncertainty about the precise value ofthe temperature behind a reflected shock than behind the incident shock,but it does not differ so much from its value calculated from the incidentshock conditions as was fist considered by Strehlow and Cohen.ll How-ever, Schlieren photographs do show that there are two cases to be considered.In the first, for polyatomic gases, strong shock interactions occur on reflec-tion of the shock wave.Diatomic gases may have an acceleration andbifuration of the reflected shock wave. They are nearer ideal conditions forshocks of moderate strength, but for stronger shocks in nitrogen, theSchlieren photographs by Holder et aZ.12 show considerable interactions be-tween the reflected shock and the boundary layer. The second case is thatof the inert gases where no bifuration of the reflected shock wave occurs, butits velocity is not exactly that calculated.Evidence that reflected shockwave properties in inert gases are more nearly those expected comes fromthe pressure measurements by Skinner and by Brabbs et aL13 and the densitymeasurements by Gardiner and Kistiakowsky and by Strehlow and Case l4which are commented on by Rudinger.15 These observations do show smallJ. N. Bradley and G. B. Kistiakowsky, J . Chem. Phys., 1961, 35, 256.loM. Camac and A. Vaughan, J . Chem. Phys., 1961, 34, 460.IIR. A. Strehlow and A. Cohen, J .Chem. Phys., 1959, 30, 257.12D. W. Holder, C. M. Stuart, and R. J. North, Aeronautical Research Councill3 C. B. Skinner, J . Chem. Phys., 1959, 31, 268; T. A. Brabbs, S. A. Zlatovich, andl4 W. C. Gardiner and G. B. Kistiakowsky, J . Chem. Phys., 1961, 34, 1080; R. A.15G. Rudinger, J . Chem. Phys., 1961, 35, 1507.Report No. 22,891 (1961).F. E. Belles, ibid., 1960, 33, 307.Strehlow and C. T. Case, ibid., 1961, 35, 150648 GENERAL AND PHYSICAL CHEMISTRYchanges in pressure and density with time behind reflected shocks, but theeffect on the temperature is not quite clear. This question is important asreactions are often studied behind reflected shock waves ; l6 reflected shocksare always used in the chemical shock tube and in the method using a massspectrometer.A method of studying atom recombination rates has been developed byBurns and Hornig l7 who have combined a flash photolysis and shock-tubeexperiment.This has the clear theoretical attraction of permitting a studyof a high-temperature recombination rate directly instead of inferring itfrom the dissociation rate and equilibrium constant, but there are manyconsiderable experimental diiliculties.There have been two important developments in producing shocks a thigh temperatures both at high densities and low densities. I n the firstcase, Stalker l8 has developed a free-piston'compression tube to give a drivergas with a high pressure and temperature. In the second, Lin and E'yfe l9have made a shock tube to work at low densities using a 24-inch diametertube.This size is essential because the tube must be large compared withthe boundary layer, as is shown by Duff's results 7 obtained in a l-in. dia-meter tube. The apparatus can be used to study chemical reactions at hightemperatures and low densities. The low densities give long distances overwhich reactions take place, but there are difficulties because of the curvatureand tilt of the shock front.There have been developments in the analysis of results as well as inmethods of obtaining them. Johannesen and Blythe 2o have given an exactmethod for analysing vibrational relaxation regions as an alternative tomethods which use some average temperature during the relaxation pro-cess.21 Computers have been used to calculate the resultant changes to beexpected in some property-for example, density-when certain rate con-stants are assumed for the reactions occurring, and comparison of measuredand calculated results enables values of several rate constants to be found(see, for example, ref.22).There is,however, a considerable number of papers concerning the ionization ofxenon (e.g., ref. 23), and the evidence obtained by Gloersen 2* that luminousshocks can produce photoionization on the walls of the shock tube ahead ofthe shock wave is of great importance in high-temperature studies wherethere is light emission. Examples of the use of a shock tube to study equi-Systems Studied.-This report does not consider ionized gas.l6 F. Freedman and J. W. Daiber, J. Chem.Phys., 1961, 34, 1271; C. E. Treanorl7 G. Burns and D. F. Hornig, Canad. J . Chem., 1960, 38, 1702.18 R. J. Stalker, Aeronautical Research Council Report No. 23,280 (1961).19 S. C. Lin and W. I. Fyfe, Phys. 'Fluids, 1961, 4, 238.2O N. H. Johannesen, Aeronautical Research Council Report No. 22,171 (1960);21D. L. Matthewo, J. Chem. Phys., 1961, 34, 639.ssR. E. Duff and N. Davidson, J. Chem. Phys., 1959, 31, 1018.23 A. P. Dronov, A. G. Sveridov and N. N. Sobolev, Optika i Spectroskop.1:ya7 1961,103, 12; H. J. Johnston and W. Kornegay, Trans. Faraday SOC., 1961, 57, 1563; P.Gloersen, Phys. Fluids, 1961, 4, 790.a* P. Gloersen, General Electric Co., Space Sciences Lab. Tech. Information ReportNo. R60 Sd 364 (April 1960).and W. H. Wurster, ibid., 1960, 32, 758.P. A.Blythe, Aeronautical Research Council Report No. 22,170 (1960)SIMPSON: REACTIONS STUDIED USING SHOCK TUBES 49librium conditions are the papers by Knight and Rink,25 who measured thedissociation energy of cyanogen and related quantities, and Treanor andWurster, l6 who measured transition probabilities in the Schumann Rungesystem of oxygen. This was done by taking absorption spectra of oxygenwhen the upper vibrational and rotational levels were populated in a mannerwhich could be calculated from the equilibrium temperature behind thereflected shock wave. However, most papers are concerned with measuringrate constants rather than equilibrium properties. These can be dividedvery roughly between cases involving an overall process, or complex reaction,and those which consider energy transfer, the dissociation of a diatomicmolecule, or a detailed study of an intermediate in a complex reaction.Overall Reactions.--Shock tubes have been used to extend the tempera-ture range in which decomposition and oxidation reactions can be studied.The pyrolysis of acetylene has been studied by Aten and Greene, using,asimple shock tube, and by Skinner, using a chemical shock tube.26 Thecracking of paraffins has also been studied by Poltorak.27 Shock ignitionof hydrocarbons has been investigated by Yamozaki and Kato.2s The de-composition of nitric acid vapours has been studied 29 and Wellman 3O hasused a chemical shock tube to study the oxidation of hydrocarbons.Chemi-cal shock tubes have been used by Boudart and his co-workers * and Skinneret aL31 to study the decomposition of methane and the pyrolysis of ethaneand ethylene.Boudart obtained a good correlation between the high- andlow-temperature studies, but found that, in contrast to the low-temperaturereactions, the homogeneous high-temperature reaction is not inhibited byhydrogen. Skinner compared his results for ethane with those computedby using a mechanism based on nine free-radical reactions.Bradley and Kistiakowsky have used a mass-spectrometer to studyreactions in a reflected shock and have investigated the polymerization andoxidation of acetylene, and the decomposition of nitrous oxide and nitro-methane.g, 32 This method has the advantage of avoiding the possibilityof reactions occurring during cooling,26 or even in the very rapid coolingeffected in the chemica.1 shock tube.Rather different from these studies is that of the hydrogen bromine reac-tion by Britton and Cole? They followed the reaction by the decrease inbromine concentration with time and were able to separate the effects dueto bromine dissociation and consumption by the formation of hydrogenbromide.Detailed Studies.-A very interesting example of a detailed study ofa reaction is the measurement of the hydroxyl concentration in a mixture of25H. T.Knight and J. P. Rink, J . Chem. Phys., 1961, 35, 199.28 C. F. Aten and E. F. Greene, Combustion and Flume, 1961, 5, 55; G. B. Skinner27 B. A. Poltorak, Zhur. $2. Khim., 1961, 35, 284.2a K.Yamozaki and Y . Kato, J . Chem. Soc. Japan, I n d . Chem. Sect., 1960, 63, 2141.2sH. Harrison, Diss. Abs., 1960, 21, 773.30 W. E. Wellman, Diss. Abs., 1960, 21, 767.s1 G. B. Skinner and W. E. Ball, J . Phys. Chem., 1960, 64, 1025; G. B. Skinnerand E. M. Sokoloski, ibid., p. 1028.3a J. N. Bradley and G. B. Kistiakowsky, J. Chern. Phys., 1961, 35, 264; J. N.Bradley, Trans. Fn~cEay Soc., 1961, 57, 1750; D. Britton and R. M. Cole, J . Phys.Chem., lQcl, 60, 1302.and E. M. Sokoloski, J . Phys. Chem., 1960, 64, 195250 GENERAL AND PHYSICAL CHEMISTRYhydrogen, oxygen, and argon heated in a shock tube.33 The hydroxylconcentration was followed by using an OH-line light source. It was foundto build to a maximum above its final high-temperature equilibrium con-centration in the way to be expected on the basis of Sugden's hypothesis offast bimolecular reactions in a flame reaching a partial equilibrium followedby slower termolecular recombination reactions.34 The results could becorrelated quite well with calculated concentrations based on assumed rateconstants for the five basic bimolecular reactions.An analogous comparison is given by Lin and Pyfe for oxygen concentra-tions in the shock heating of air in strong shocks at low densities.lS Thisis of interest in showing that at these very high temperatures, calculationswhich assume that vibrational equilibrium is complete before chemicalreactions begin do not agree with the results as well as those treating vibra-tional excitation simultaneously with chemical reaction.Vibrational relaxation in carbon dioxide has been studied by Witteman 35who quotes relaxation times and gives calculations to show whether thereshould be separate vibrational relaxation times for the doubly degeneratebending mode and the symmetric stretching mode.A similar question ismultiple vibrational relaxation times for dibromomethane. This has beentreated theoretically and experimentally for low temperatures by Dickensand Schofield36 and Meyer.36 The problem here is whether translationalenergy is transferred to the different vibrational modes by independent pathseach with its own relaxation time, or whether the slow step is the transferof energy to one vibrational mode which is rapidly equilibriated with theothers giving only one overall relaxation time.The vibrational relaxation of carbon monoxide has been studied bylSilatthews21 using a shock tube and interferometer and by Gaydon andHurle 37 from temperature measurements using line reversal.It has beenmeasured also by using a spe~trophone.~~ These shock studies agree fairlywell, but give shorter times than those measured by Windsor, Davidson, andTayl~r.~S The correction suggested by Decius 40 to the results of Windsoret al. makes this difference greater rather than smaller; it may be due toimpurities reducing the relaxation time in the first case, and the results maybe criticized as the relaxation was measured over a condition of changingtemperature.Parker 41 has measured vibrational relaxation times for oxygen acoustic-ally and concludes that the high-temperature shock-tube results obtained byBlackman and by Byron 42 give relaxation times that are too short; they33G.L. Schott, J . Chem. Phys., 1960, 32, 710.34 E. M. Bulewicz, C. G. James, and T. M. Sugden, Proc. Roy. SOC., 1956, A , 235, 89.35 W. J. Witteman, J . Chem. Phys., 1961, 35, 1.36P. G. Dickens and D. Schofield, J . Chem. Phys., 1961, 35, 374; N. J. Meyer,37 A. G. Gaydon and I. B. Hurle, Aeronautical Research Council Report No. 22,55438W. E. Woodmansee, Dim. Abs., 1961, 22, 105.30M. Windsor, N. Davidson, and R. Taylor, J . Chenz. Phys., 1957, 37, 315.40 J. C. Decius, J . Chem. Phys., 1960, 32, 1262.41 J. G. Parker, J . Chem. Phvs.. 1961, 34. 1763.ibid., 1960, 33, 487.(1961).42N.Blackman, J . Fluid Meih.,. 1956,. 1, 61; S. Byron, J . Chem. Phys., 1959, 30,1380SIMPSON : REACTIONS STUDIED USING SHOCK TUBES 51had been consistent with earlier measurements of velocity of sound at roomtemperature.Vibrational relaxation times for nitric oxide computed by using an interac-tion potential from viscosity measurements and the theory of Schwartz ,Slawsky, and Herzfeld are longer than those observed. Experimental valueshave been obtained by using a shock tube and ultraviolet absorption and in-frared emission. The ultraviolet absorption method uses the intensity changeof the yol band in absorption to measure increase in population of the firstvibrational level of the ground state. The infrared emission from the 1-0and 2-0 transitions gives a direct measure of the changes in population ofthese vibrational levels.These results agree with each other, and with ameasurement of the velocity of sound 5 and the results of a flash-photolysisinvestigation. 43 It is interesting that in a shock-tube investigation ofrelaxation in the A2E + excited state of nitric oxide the ratio of the relaxationtimes for the 2-1 and 1-0 transitions have been measured and found toagree with a theoretical calculation. 44The very great interest in the dissociation and recombination reactionsof simple molecules is clear from papers concerned with calculations pub-lished during 1960 and 1961,45 while practical studies have been made withbromine, hydrogen, nitric oxide, and oxygen.The decomposition rate of nitric oxide was followed by ultraviolet absorp-tion using a reflected shock wave.l6 Burns and Hornig l7 have measureda high-temperature recombination rate for bromine.They give one pointfor the rate of bromine atom recombination at 950" c . It would seem tobe worthwhile to try to extend the direct flash photolysis to higher tempera-tures so as to compare these two methods. Britton 46 has studied the rateof dissociation in the presence of argon, helium, nitrogen, carbon monoxide,oxygen, and carbon dioxide. With the diatomic diluents the situation wascomplicated by the simultaneous occurrence of vibrational relaxation anddissociation.Hydrogen dissociation has been studied by Gardiner and Kistiakowsky 47from density changes in hydrogen-xenon mixtures followed by X-rays; byGaydon and Hurle 37 using temperature measurements; and by Patch 6by following the concentration of hydrogen molecules from their vacuum-ultraviolet absorption.Gaydon and Hurle used hydrogen-argon mixturescontaining 50% or 30% of hydrogen and expressed their results as relaxa-tion times, it being assumed that dissociation was not caused by the argon.The argon results agreed with those from earlier studies.43 N. Basco, A. B. Callear, and R. G. W. Norrish, Proc. Roy.Soc., 1961, A, 260,459.44 W. Roth, J . Chem. Phys., 1961, 34, 999, 2204.45 ( a ) E. Bauer and M. Salkoff, J . Chem. Phys., 1960, 33, 1202; ( b ) D. L. Bunker,ibid., 1960, 32, 1001; (c) J. C. Keck, ibid., p. 1035; ( d ) E.E. Nikitin, Doklady Akad.Nauk S.S.S.R., 1960, 132, 395; (e) E. E. Nikitin and N . D. Sokolov, ibid., 1959, 124,366; (f) E. E. Nikitin, 2hur.Ji.z. Khim., 1959,33,1893; (9) E. E. Nikitin and N. Sokolov,J . Chem. Phys., 1959, 31, 1371; (h) A. I. Osipov, Zhur. $2. Khim., 1961, 35, 1524;(i) A. I. Osipov, Doklady Akad. Nauk S.S.S.R., 1961, 13'7, 833; ( j ) G. Porter and J. A.Smith, Proc. Roy. SOC., 1961, A , 261, 28; ( k ) H. 0, Pritchard, J . Phys. Chem., 1961, 65,504; ( I ) H. 0. Pritchard, Cunad. J . Chem., 1960, 38, 319; ( m ) K. E. Shuler and R.Zwanzig, J . Chem. Phys., 1960,33, 1778; (n) K. E . Shuler, ibid., 1959,31, 1375; (0) E. V.Stupochenko and A. I. Osipov, Zhur. Jiz. Khim., 1959, 33, 1526.46D. Bitton, J . Phys. Chem., 1960, 64, 742.4 7 W.C. Gardiner and G. B. Kistiakowsky, J . Chem. Phys., 1961, 35, 176552 GENERAL AND PHYSICAL CHEMISTRYThe temperature dependence of the rate constants for bimolecular dissocia-tions given by Gardiner and Kistiakowsky for the dissociation in xenonsuggest that a t high temperatures argon may not be much less efficient thanhydrogen. They used either 17% or 48% of hydrogen and found that thelarge change in temperature during a dissociation gave some uncertainty inthe temperature dependence of the rate constants. Patch was able to useas little as 1% of hydrogen in argon. He compares recombination rateconstants, calculated from dissociation rates and equilibrium constants, withthe results of the shock-tube studies made by Sutton and Rink who usedabout 3% and 10% of hydrogen in argon. Patch obtains Kr,Ar 2.1 x 1014,with K,,,, 2-1 x 1015 and Kr,= 1.4 x l0l6 cm.6 mole-2 sec.-l at 3500"~.Sutton and Rink's results do not differ by a factor of more than three or fivefrom these values, while Gardiner and Kistiakowsky obtained 1.3 x lo1*for Rr,=*.Patch compared his high-temperature value of Kr,, with recom-bination constants from dischwge- tube experiments at room temperature ;the results are quite similar.The rate of dissociation of oxygen has been determined by using X-ray ab-sorption by Rink, Knight, and Duff 48 and by Cheswick and Kistiak~wsky;~Sby vacuum-ultraviolet absorption by Camac and Vaughan,lo Anderson,Gand Losev;SO and by use of an interferometer by Byron 42 and Matthews.51The results have been compared by Duff as recombination rate constantsa t 3500" K for the third bodies molecular oxygen, xenon, argon, and atomicoxygen.For argon as a third body theresults by Anderson, Camac, and Byron are within a factor of two. Thecomparison should be thought of as one between dissociation rates, as ineach case the recombination constant is derived from the equilibrium con-stant a t 3500"~ and dissociation rates, but there is some question its towhether this is the true recombination rate.Camac and Vaughan's results are of great interest as in experimentsabove 7500" K these authors found coupling between the rates of vibrationalequilibrium and dissociation. This is consistent with Lin and Fyfe's resultson the reactions of high-temperature air.lg Camac and Vaughan concludedthat at these high temperatures lack of vibrational equilibrium reduces therate of dissociations by more than a factor of two.However, their resultsfor dissociation of oxygen in argon can be well expressed by using the dissocia-tion energy D in the classical kinetic theory curveThe results agree quite well.KAr = 6 x 1013(D/RT)exp(-D/RT)for the temperature range 3500-7000" K. This uses measurements whichinvolve the assumption of vibrational equilibration being fast compared todissociation. They have used these data and calculated equilibrium con-stants to calculate recombination rate constants which they have comparedwith those obtained by use of Keck's theory.An outstanding problem in considering recombination rates is the de-crease in rate which occurs as the temperature increases.This is found from48 J. P. Rink, H. T. Knight, and R. E. Duff, J . Chem. Php., 1961, 34, 1942.4* J. P. Cheswick and G. B. Kistiakowsky, J . Chem. Phys., 1958, 28, 956.6 0 S . A. Losev, Doklady Akad. Nauk S.S.S.R., 1958, 120, 1291.6lD. L. Matthews, Ph.ys. Pluids, 1959, 2, 170SIMPSON: REACTIONS STUDIED USING SHOCK TUBES 53flash-photolysis experiments in the temperature range 300-500 O K, fromshock-tube results at high temperatures and by comparisons of these resultswith rates obtained at room temperature by discharge experiments.Bunker 4Bb considers the mechanics of the reaction X + X + M + X, + Mto proceed either by the path X + X --+ X2x ; X,x + M + X, + M,or X + M -+ XM; XM + X -+ X, + M with van der Waals’ interactionbetween X and M.Such mechanisms give negative-temperature coefficients.Porter and Smith 45i also consider recombination between iodine atomswith different third bodies and conclude that charge-transfer complexesare important.Keck has derived results for the maximum rates of atom recombination.He represents the reaction by the motion of a point in phase space acrossa surface dividing the initial and the final state and calculates the rate ofcrossing this in one directi0n.45~ To obtain results he has to specify thepotentials between the particles and, unfortunately, there are few data onthree-body potentials. He compares his calculated maximum recombinationrate constants with experimental results for X + X + Ar --+ X, + Arwhere X, is oxygen, iodine, bromine, and nitrogen.The results of low-temperature flash photolysis fall quite close to the theoretical curves-thecase of bromine being improved by the separation of the third-body effectsof bromine and argon in Givens and Willard’s recent results.52 The shock-tube results, including recent ones on oxygen, fall below the calculatedcurve. The low-temperature results for oxygen considered by Keck andby Bauer 45 are recombination rate constants from discharge experiments.The system has been investigated by Harteck and his co-workers and byKretschner by following the concentrations of oxygen atoms by the 0 + NOreaction;53 references to other papers are given by Linnett and his co-workers.54 The low-temperature results are complicated by the competingreactions 0 + 0 + M-+ 0, + M and 0 + 0, + M-+ O3 + &I, but theozone reaction is not important at the high temperatures of the shock-tubee~periments.~8 This difficulty is avoided by Morgan, Elias, and S ~ h i i T , ~ ~who produced oxygen atoms by the reaction N + NO + Nz + 0 andmeasured the recombination rate with nitrogen as the third body. SinceBunker and Davidson’s calculations 56 agree with experimental results foriodine-atom recombination in assigning nearly equal third-body effects tonitrogen and argon it is reasonable to consider that the rate constant for0 + 0 + Ar+ 0, + Ar will be close to the value found for nitrogen andto use this result obtained by ScM.Keck considers two reasons for thedifference between the calculated and experimental results at high tempera-tures. First, instead of being a simple one-way process, recrossing of thebarrier between initial and final states may become more important a t hightemperatures and, secondly, the differences might be due to the choice ofthe three-body potential. It is possible also that the experimental results63 W. G. Givens and J. E. Willard, J . Amer. Chenz. SOC., 1959, 81, 4773.6s R. R. Reeves, G. Mannella, and P. Harteck, J . Chem. Phys., 1960, 32, 632.64P. G. Dickens, R. D. Gould, J. W. Linnett, and A. Richmond, Nature, 1960,66 J. E. Morgan, L. Elias, and H. I. Schiff, J . Chem. Phys., 1960, 33, 930.6 6 D. L. Bunker and N.Davidson, J . Amer. Chem. SOC., 1958, 80, 6090.187, 68654 GENERAL AND PHYSICAL CHEMISTRYmay be low, for if the rate of dissociation a t high temperatures is limited bythe rate of population of the vibrational levels then Kd will be less than theequilibrium value corresponding to the product of the equilibrium constantand the recombination rate constant, and so K,, calculated as Kd/K, Willbe small.Oxygen-atom recombination rates have been treated by Bauer 45a alsousing quantum mechanics. He considered the more complicated reactionusing an interaction potential derived from experimental results, of vibra-tional relaxation in oxygen. He found that recombination takes place intohighly vibrationally excited states and obtained rate constants which agreewithin a factor of three with the experimental results obtained by Harteckand his co-workers 53 and Matthews’s 51 shock-tube results.This is encourag-ing but it must be remembered that a greatly simplified theoretical modelwas used and there are these uncertainties in the experimental results.The question whether the relation Kd/Kr = K can be used at conditionswhich are not those of equilibrium depends on whether .& equals the equi-librium value, Kd,eq., for examples by Nikitin and Sokolov 45e show thatK, would be close to Kr,eq.. The system usually considered is that of A,dissociating in a large heat bath of molecules M at a constant temperature T.Dissociation probably occurs from vibrational levels near the dissociationlimit and the question is to what extent these levels are depleted comparedwith the Boltzmann value for the temperature T.The question is consideredby Shuler, Nikitin, Osipov, and others,45 and results of calculated Kd arecompared with shock-tube results. Nikitin and Sokolov and Osipov andhis co-workers both consider that the Boltzmann distribution is disturbed athigh temperatures, and derive equations for &. Shuler also calculated thedisturbance of the Boltzmann distribution, using the assumption commonlymade that, except near the dissociation limit, the vibrational energy onlychanges by one quantum steps, Av I = 1. However, he stated that thesecalculations should not be considered too seriously in view of his work withMontroll that showed that a one-step-at-a-time “ ladder climbing ” mech-anism gave dissociation rates that are much too slow compared with thoseobserved.57 The later paper of Shuler and Zwanzig shows that a harmonicoscillator undergoing impulsive hard-sphere collisions has a considerableprobability of acquiring vibrational energy in steps with I AY I > 1.Thisshould be contrasted with the recent paper by Pritchard who based his cal-culations on a formula for transition probabilities given by Jackson and Mottand concluded that excitation occurs by single steps and that the rate ofdissociation is affected by a lack of vibrational equilibration which becomesmore serious as the temperature is raised.45kCamac and Lin’s experimental results do show that at sufficiently hightemperatures a slow rate of vibrational equilibration does affect the rate ofdissociation.As the temperature is lowered, measured vibrational relaxa-tion in oxygen becomes faster relative to dissociation. However, these67E. W. Montroll and K. E. Shuler, “Advances in Chemical Physics,” ed. L.Prigogine, Interscience Publ. Inc., New York, 1958, Vol. 1, p. 361BIS'HOP : NUCLEAR MAGNETIC RESONANCE 55measurements are concerned with the population of low-lying vibrationallevels and it is not clear how far the populations of the upper levels are fromtheir extremely small equilibrium values. Thus, it can be concluded thatdespite considerable progress neither shock-tube results nor theoreticalcalculations yet give a complete picture of the mechanism of vibrationalexcitation and dissociation.It may be true that Ed = K,K only appliesa t equilibrium, but it is not certain under what conditions it is a goodapproximation. However, recent shock-tube studies have given informationon a wide variety of subjects.C. J. S. M. S.6. NUCLEAR MAGNETIC RESONANCETHE present Report is concerned mainly with recent developments in thetheory and applications of the spin coupling and chemical shift parameters,and the ways in which these may be deduced from the high-resolution nuclearmagnetic resonance spectra of liquids and gases. Some chemical aspects ofrelaxation times and of the broad-line spectra of solids are also discussedbriefly. The literature surveyed is mainly that of the parst two years, sincethe previous Report on this subject by Pop1e.lInterpretation of Spectra.-The greater part of molecular informationfrom the nuclear magnetic resonance spectra of liquids and gases is obtainedfrom the chemical shift and spin coupling pararneters.l, For a weaklycoupled system, where the coupling constant Jij between each pair of mag-netically non-equivalent nuclei i, j is small compared with their difference inchemical shift, the parameters (but magnitude only, not sign, of Jij) areevident by inspection of the '' first-order " spectrum of symmetrical multi-plets.In more strongly coupled cases, spin-coupling causes significant mix-ing of the first-order eigenstates with distortion of both line positions andintensities from the symmetrical multiplet patterns, and appearance ofnew (" combination ',) lines which were forbidden in first order.Quantum-mechanical analysis is then necessary, and can often be simplified by useof symmetry properties of the spatial distribution of the nuclei and theircoupling interactions, and also by neglect of small mixing terms. If signi-ficant mixing can thereby be restricted to two of the first-order eigenstatesa t a time, then all transition energies and intensities can be expressed insimple algebraic form and t'he parameters can be found directly. Thesemethods have been reviewed by Roberts and C ~ r i o , ~ and the latter illus-trates the appearance of many spectral systems with variation of couplingstrength. In the nomenclature of Pople et aL19 2 for nuclei of spin 9, suchalgebraic treatment has been extended to the systems ABRX5 and AB,X,6J.A. Pople, Ann. Reports, 1959, 56, 78, and references therein.J. A. Pople, W. G. Schneider, and H. J. Bernstein, " High Resolution N.M.R.,"J. D. R o p t s , " An Introduction to Spin-Spin Splitting in High ResolutionB. D. W. Rao and P. Venkateswarlu, Proc. Indian Acad. Sci., 1960, 52A, 109.(a) R. J. Abraham, E. 0. Bishop, and R. E. Richards, Mol. Phys., 1960, 3, 485;McGraw-Hill, 1959.N.M.R. Spectra, W. A. Benjamin Inc., N.Y., 1961.4P. L. Corio, Chem. Rev., 1960, 60, 363.(b) P. Diehl and I. Granacher, J. Chem. Phys., 1961, 34, 184656 GENERAL AND PHYSICAL CHEMISTRYwhilst Diehl, Pople, and Schaefer 7 have shown that all systems of typeA,B, . . . R, . .. Xu . . . (my n, p, q are any integers) may be included inthis scheme provided that each nucleus of a particular magnetic environmentis equivalently coupled to those of any other environment. Under theseconditions, the spectrum is independent of mutual coupling within each ofthe groups A,, B,, R, . . ., and may be considered as a superposition ofspectra for the various combinations of these groups, considered as “ com-posite particles,” with fixed total spin.8 This is exemplified by analysisof the systems ABX,, ABR3X, and AB,X,. Hoffman and Gronowitz havealso analysed the system ABT, where T = deuteron of spin unity, as aspecial case of ABX, in which the composite particle X, cannot have itsconstituent spins of Q opp~sed.~ The general three-spin system ABC isoften encountered, and although mixing of states in sets of three is involved,exact analytical treatment is discussed in three papers.10, 11, 1 2Slight departures from a more readily soluble case can be convenientlytreated by including the effect of small additional mixing terms as a pertur-bation upon the simpler system.Reilly and Swalen have considered thesystems ABK l3 (intermediate between ABX and ABC) and ABKY 1 4 bysecond-order perturbation, and applied them to an analysis of the protonspectra of some epoxides. Cavanaugh and Dailey15 have analysed theproton spectra of the propyl group (A,B,C,) in a number of compounds, byperturbation to third order. For strongly coupled spectra the analyticalsolution is usually impracticable, however, and is replaced by iterative orfrial-and-error nuinerical solution by computer to match a set of eigenvaluesdeduced from the spectral line positions. Elements for setting up thenuclear-spin Hamiltonian matrix are tabulated for the systems ABCX,16A2B6,17 and AB,C2X l8 and applied to spectral analyses of vinyl fluoride,propane, and fluorobenzene, respectively ; pent-2-yne has been treatedexactly as an A3B,C3 system.lg Analyses of ethyl compounds are discussedin a later section.A novel extension of the deuterium-substitution method of simplifyingcomplex proton spectra has been given recently by Garnett et aL20 Cata-lytic “ massive deuteration ” in favourable cases replaces H largely by Dat random sites, so that the remaining protons are likely to couple only todeuterium.The 1H spectrum then collapses to fairly narrow bands at eachibid., 3, p. 557.7 J. A. Pople and T. Schaefer, MoZ. Phys., 1960, 3, 547; P. Dish1 and J. A. Pople,*R. A. Hoffman, Arkiv Kemi, 1961, 1’4, 1.*R. A. Hoffman and S. Gronowitz, Arkiv Kenti, 1961, 16, 501.10 W. Brugel, T. Ankel, and F. Kruckeberg, 2. Elektrochem., 1960, 64, 1121.11s. Castellano and J. S. Waugh, J . Chem. Phys., 1961, 34, 295.12 S. S. Jha, PTOC. Indian Acad. Sci., 1961, 54A, 13.13C. A. Reilly and J. D. Swalen, J. Chem. Phys., 1960, 32, 1378.14C. A. Reilly and J. D. Swalen, J. Chem. Phys., 1961, 34, 980.15 J. R. Cavanaugh and B. P. Dailey, J. Chem. Phys., 1961, 34, 1094.16 C. W. Banwell and N. Sheppard, Proc. Roy. Xoc., 1961, A , 263, 136.1 7 D.R. Whitman, L. Onsager, M. Saunders, and H. E. Dubb, J . Chem. Phys.,185. Fujiwara and H. Shimizu, J. Chem. Phys., 1960, 32, 1636.19 B. Braillon, J . Chim. phys., 1961, 58, 495.Zo J. L. Garnett, L. J. Henderson, W. A. Sollich, and G. V. D. Tiers, Tetruhedron1960, 32, 67.Letters, 1961, 516BISHOP : NUCLEAR MAGNETIC RESONANCE 57chemical-shift position, and the latter have been found for a series of mono-substituted benzenes.It has been demonstrated recently that, even in quite simple systems,a spectrum containing close and unresolved lines may sometimes bematched, to within the limits of experimental accuracy, by a wide range ofrelative values of coupling constants which on casual inspection appearto be equal. This aspect of systems ABX, A,X2, and ABXY has beenstudied by Abraham and Bernstein,,l and of A2B2 by Grant and Gutowsky,22and consequent errors in previous analyses are noted.Anet 23 has notedrecently that the practice of equating the proton doublet splitting of asecondary methyl group to the coupling constant may give a low estimate ifthe spectrum is not first-order. As the chemical shift between CH and CH,in the grouping CHCH, is diminished, new lines appear mainly within thefirst-order doublet due to CH, and may not be resolved from it.In view of theoretical interest in the sign of coupling constants, deter-mination of their relative signs within a given spin system has becomeincreasingly important. This can be effected by conventional analysis onlyunder conditions for which the analysis itself is fairly =cult-thus a systemof at least three non-equivalent and strongly coupled nuclei is then necessaryto determine all the relative signs.Significantly, a direct method fordetermining relative signs by spin decoupling has been reported recentlyby Maher and Evans 24 and developed by Freeman and Atleast three non-equivalent nuclei are again necessary, but these are notrequired to be strongly coupled. The method is most effective underconditions of weak coupling, and in this sense is complementary to conven-tional analysis. Turner 26 has utilized beat patterns to determine couplingconstants too small to cause resolvable line splitting, whilst Brown andThompson 27 have suggested the use of ‘‘ free precession ” signals a t verylow field for direct determination of coupling constants.Electron-coupled Nuclear Spin-spin Interactions.-The general expressionfor the energy of interaction (J = coupling constant, usually given in c/sec.)has been given by Ramsey.l, Inter-proton coupling JHH has been mostwidely investigated experimentally, and is also the most amenable to theo-retical interpretation since it depends mainly on the Fer& contact term.This is the only term which does not involve use of angular-dependentorbitals, whilst the electron distribution about a hydrogen atom is wellrepresented by the 1s atomic orbital.The contact mechanism for spin-coupling depends on weak admixture of excited triplet electronic states withthe ground singlet state, and in the absence of knowledge of most excitationenergies and excited-state wave functions, it has been usual practice to usean approximation requiring only the mean triplet excitation energy and thetotal ground-state wave function.Valence-bond treatment, mainly by2lR. J. Abraham and H. J. Bernstein, Canad. J . Chem., 1961, 39, 216.22D. M. Grant and H. S. Gutowsky, J . Chem. Phys., 1961, 34, 699.23 F. A. L. Anet, Canad. J . Chem., 1961, 39, 2262.24 J. P. Maher and D. F. Evans, Proc. Chem. SOC., 1961, 208.R. Freeman and D. H. Whiffen, MoZ. Phys., 1961, 4, 321; R. Freemm, {bid.,28 J. J. Turner, Mol. Phys., 1960, 3, 417.27R. J. S. Brown and D. D. Thompson, J . Chem. Phys., 1961, 34, 1580; 35, 1894.p. 38558 GENERAL AND PHYSICAL CHEMISTRYKarplus, achieved notable successes in predicting the magnitudes andmarked steric dependence of JHH upon interbond angle in the system HCH,upon the dihedral angle in substituted ethanes, and upon cis-trans-isomerismin coupling across an olefinic bond.1 According to this treatment, finitecoupling depends on inclusion of non-perfect pairing structures, and onlya-type bonds were used.The results are in good agreement with experi-ment in many cases.1 This is confirmed by more recent studies describedbelow, although other effects are sometimes significant. The validity of theaverage energy approximation has been challenged by McLachlan 28 and byAlexander, 29 who concludes, however, from an alternative valence-bondapproach, that Karplus's procedure is largely justified in the particularsystems studied.This view is maintained by Karplus in recent papers.30The case of proton coupling across a system of single bonds being con-sidered first, the commonest interaction (JVic) observed between protonson adjacent carbon atoms occurs when the re-orientation rate about theC-C bond is considerably greater than Jvic, so that the single observed JHHis the mean value for all conformations. The theoretical coupling predictedby Karplus by averaging over all values of the HCCH dihedral angle (4)is 4.2 c/sec. (positive), which can be compared with the narrow experimentalrange of 6-8 c/sec., including values recently found in propane l7 andpropyl derivatives.15 A more critical test of Karplus's theory is providedby cases of known geometry, having a rigid ring system or at least a highlyfavoured conformation.Here, theory predicts maxima for 4 = 180"(Jtrans) and 0" (Jcis), with Jtrans > Jcis, and approximately zero couplingfor 4 = 90". Earlier data are considered by Jackman (ref. 31, p. 84),and it is noted that some contrary evidence from the inferred equality ofJtrans and Jcis in A,B, systems is invalid 22-e.g., they may be considerablydifferent in trans-dibromocyclopropane, although they are probably similarin ,8-propriolactone. Anet 32 has reported values of JHH for $ = 0", 44",79", and 120" in a camphane bridged-ring system, and finds good agreementwith Karplus's predicted values in each case. A value for r) = 60" reportedby Brownstein 33 in a heavily substituted ethane also agrees well with theory.Musher 34 finds coupling for + = 60", 180" in a cyclohexene system some2-3 c/sec.larger than predicted-cf. the " free rotation " case discussedabove. Extensive study of epoxides 13, 14, 35, 36 has revealed an interestingsituation in that Jcis (3$ to 5 c/sec.) is always larger than Jtrans (2 to 34c/sec.), the opposite of usual behaviour in saturated and unsaturated mole-cules. This is qualitatively consistent with Karplus's theory, since an" eclipsed ethane " structure would have qb considerably less than 180" forthe '' trans " interaction.z*A. D. McLachlan, J . Chem. Phys., 1960, 32, 1263.zOS. Alexander, J . Chem. Phys., 1961, 34, 106.3oM. Karplus, J .Chem. Phys., 1960, 33, 941; 1842.31 L. M. Jackman, " Applications of N.M.R. Spectroscopy in Organic Chemistry,"3aF. A. L. Anet, Canad. J . Chem., 1961, 39, 789.38S. Brownstein, Canad. J . Chem., 1961, 39, 1677.34 J. I. Musher, J . Chem. Phys., 1961, 34, 594.*6C. A. Reilly and J. D. Swalen, J . Chem. Phys., 1961, 35, 1322.36 J. I. Musher, Mol. Phys., 1961, 4, 311.Pergamon, London, 1959BISHOP : NUCLEAR MAGNETIC RESONANCE 59JHH between protons attached to the same carbon atom is predicted byKarplus to decrease steeply with increasing bond angle, from +32-3 c/sec.at loo", through 12.5 c/sec. a t the tetrahedral angle, and becoming negativea t 125". Data presented by Banwell and Sheppard 37 for compounds ofknown HCH angle show a good correlation with the latter as predicted,although theoretical values for olefins are somewhat higher than observed.Experimental values where carbon is in sp3 hybridization are scarce-arecent value of 12.36 c/sec.is in good agreement with theory.34 The theo-retical predictions must, however, be treated with caution in view of tworecent reports of opposite signs of Jge, and Jvic in saturated molecules.Fraser et al. find this in substituted di0xalans,3~ and Kaplan and Robertsin diethyl sulphite.39 The usual range of JHHgem values in the vinyl groupCH,:CHX is from -3 to +2 c/sec. The analogous coupling of 3.92 c/sec.in diketen is reasonably ascribed to a decrease in HCH bond angle below120" due to bond strain in the adjacent ring carbon. Unusually large valuesin organometallic compounds, especially vinyl linked to aluminium (6.3c/sec.)QO and lithium (7.1 c/sec.),*l are almost certainly due to factors otherthan change in bond angle, since they are paralleled by large values for othercoupling constants in the systems-see below.A large value reportedin acrylic acid 42 does not agree with other analyses for this com-pound.10, l1 Hiroike 43 predicts, from an alternative valence-bond treat-ment of saturated systems, that JHH will decrease as the electronegativityof the atom chemically bonded to either proton increases: 12 c/sec. is cal-culated for methane.Excepting the low values of Jgem, JHH through a a-bond system isobserved to attenuate very rapidly with increasing number of bonds betweenthe protons-by a factor of 1/10-1/20 for each additional bond.Couplingacross four a-bonds is observed only in geometrically favourable systems,when it is -1 c/sec.;44 also an exceptionally large value of -7 c/sec. isreported in a bicyclo[2,l,l]hexane ~ystern.~5 Coupling of &0.4 46 or 0.54 47c/sec. between the methyl groups in acetone has been detected from the13CH satellite spectrum, and has been ascribed to a n-electron mechanismarising from the carbonyl group.47 This should be nega,tive, and a similarn-contribution of -1.5 c/sec. to JHHgBm in vinyl compounds is postulated-cf. discussion above.The experi-mental ratio and order of magnitudes of Jcis, Jtrans in the system H*C:C*Hare quite well reproduced in Karplus's treatment of coupling via the37 C.N. Banwell and N. Sheppard, Mo2. Phys., 1960, 3, 351.38 R. R. Fraser, R. V. Lemieux, and J. D. Stephens, J . Amer. Chem. SOC., 1961,39 F. Kaplan and J. D. Roberts, J . Amer. Chem. SOC., 1961, 83, 4666.40D. W. Moore and J. A. Happe, J . Phys. Chem., 1961, 65, 224,JHH across a multiple bond follows a different pattern.83, 3901.C. S. Johnson, M. A. Weiner, J. S. Waugh, and D. Seyforth, J . Amer. Chem. SOC.,Y. Arata, H. Shimizu, and S. Fujiwara, J . Phys. SOC. Japan, 1960, 15, 2119.43E. Hiroike, J . Phys. Soc. Japan, 1960, 15, 270.44D. R. Davis, R. P. Lutz, and J. D. Roberts, J . Amer. Chem. SOC., 1961, 83, 246.45 J. Mainwald and A. Lewis, J . Amer. Chem. SOC., 1961, 83, 2769.4'3H. Dreeskamp and E. Sackman, 2. phys. Chem. (Frankfurt), 1961, 27, 136.47 J.R. Holmes and D. Kivelson, J . Amer. Chem. Soc., 1961, 83, 2959.1961, 83, 130660 GENERAL AND PHYSICAL CHEMISTRYa-electrons alone-experimental values tend to be somewhat larger than thecalculated results ( +6.1, 11 -9 c/sec., respectively). Longer-range inter-actions are smaller, but attenuate only slightly with increasing number ofintervening bonds, whether single or multiple. Avalue of 1.1 c/sec. over7 bonds is reported in hexa-2,4-diyn-1-01.~~ This suggests that the n-electrons cause the major contribution JHH(n) to the long-range couplings,and a quantitative valence-bond treatment of this effect in non-aromaticsystems has been given recently by K a r p l ~ s . ~ ~ It arises from c-n exchangeterms, and correspondence between these and the isotropic hyperfine con-stants in related free radicals has enabled JHH(n) to be deduced for severalsystems from empirical values for the latter.Comparison with experi-mental values indicates that coupling constants in a system HC,H, contain-ing unsaturation, are dominated by a-contributions for n = 2, and byn-contributions for n > 2. JHH(n;) across an CiC bond is predicted, andobserved to be about twice as great as that across C:C, and in acetyleneitself accounts for a larger fraction (-Q) of the total coupling (9.1 c/sec.)than in ethylene. Of considerable interest is the prediction of alternatingsigns for JHH(n) for each additional C-C bond,30 and the confirmation ofnegative values for n = 3,'s 259 309 4% a9, 50 and positive values for n = 4,489 51is good evidence for the validity of the conclusions.Furthermore, nearequality of the cis- and trans-interactions in the system H*C:C*CH*~~Y 5% 53in sharp contrast to that for H*C:C-H, is further evidence for dominance ofthe n-coupling mechanism, which is independent of the geometry. Jcis issometimes slightly larger than Jtrans in this system.50, 53 Hoffman andGronowitz 48 have pointed out that the very slight attenuation of JHH(n)expected (with change of sign) on replacing a hydrogen atom by a methylgroup may be used as a measure of the extent of n-coupling and hypercon-jugation. They infer that this occurs in dimethylformamide (see alsoheteroaromatic compounds, below). Extensive investigations of vinyl com-pounds, especially by Briigel et al.,la have enabled substituent effects, notcovered by Karplus's results, to be clearly established.Each JHH withinthe vinyl group *CH:CH* shows a good linear correlation with the electro-negativity (E) of the atom (X) immediately attached to the vinyl group;moreover the plot of each J against E has the same slope (J decreases withincreasing E ) . This was &st noted by Banwell and Sheppard 37 andextended to the exceptionally large couplings in vinyl-lithium (trans 23.9,cis 19-3, gem 7.1 c/sec.).41 J against E for thirteen elements inposition X is given by Waugh and cast ell an^.^^ A very low value of Jcis(2.0 c/sec.) is found in ~is-1,2-difluoroethylene.5~Many data on JHH between ring protons in aromatic compounds haveA plot of c48R.A. Hoffman and S. Gutowsky, Arkiv Kemi, 1960, 16, 471.r S S . Alexander, J . Chem. Phys., 1960, 32, 1700.aoA. A. Bothner-By and C. Naar-Colin, J . Amer. Chem. SOC., 1961, 83, 231.alB. Braillon, J . Chirn. phys., 1961, 58, 495.6a J. H. Richards and W. F. Beach, J . Org. Chem., 1961, 26, 623.6s R. R. Fraser and D. E. McGreer, Canad. J . Chem., 1961, 39, 505, and referencess4 J. S. Waugh and S. Castellano, J . Chem. Phys., 1961, 35, 1900.ssT. D. Coyle, S. L. Stafford, and F. G. A. Stone, J., 1961, 743.therein.BISHOP : NUCLEAR MAGNETIC RESONANCE 61been collected by Hoffman and Gronowitz 56 (which see for earlier refer-ences). Jortho between protons on adjacent carbon atoms is significantlysmaller (1-3 to 5.8 c/sec.) in heteroaromatic rings than in substitutedbenzenes (7.0 to 9.3 c/sec.)y except J3,4, remote from the hetero-atom, inpyridines and quinolines 57, A linear decrease inJOr,,,(H;C*C*Hb) with increase in sum of the inter-bond angles H,CC, CCHb hasbeen reported.59 Coupling again attenuates with increasing number ofbonds between the nuclei, with the exception that it is abnormally low whenthe shortest bond path lies across a nitrogen atom (no values are recordedfor J 2 , 5 in pyrroles).J,,, is not equal to J,,, in furans,21, 6o contrary to earlierinterpretation of their spectra. Few complete determinations of relativesigns have been made, but all coupling constants within each of the systems1,2,4-trichlorobenzeney61 thiophen,62 and 2-furoic acid 25 are of similar sign(assumed positive).A theoretical valence-bond estimate of the n-electroncontribution to JHH in benzenoid systems by McConnell indicates that thisis very small (0.45 c/sec. for Jortho; less for long-range coupling), and isnegative for Jmeta. Both observed magnitudes and signs indicate that theortho- and meta-interactions are dominated by 0-electron coupling, althoughthe n-contribution to Jpara may be appreciable. This is in marked contrastto JHH(n) in aliphatic systems with largely localized double bonds (seeabove). Coupling from side-chain to nucleus is usually undetectable, butinteractions of -1 c/sec. have been found in five-membered heterocyclicrings.48, 6o Comparison of these values with those of corresponding intra-ring couplings indicates that JHH(n) is more important here than in benzene(see earlier)--estimates of 20% of the total J 2 , 3 in thiophens, and 50-100~0in pyrroles and furans, have been made.48 " Cross-ring " coupling of similarmagnitude between protons attached to different aromatic rings has beendetected in the quinoline 57 and thieno[3,2-b Jpyrrole 63 systems,Coupling involving nuclei other than hydrogen is often considerablylarger than that between two protons, and the contact mechanism need notpredominate.It does appear to do so, however, in JHF and JFF across thedouble bond in fluoroethylenes, since calculation by Karplus, similar to thatfor JHH, predicts values close to those observed (again, Jtram > Jcis). Manycoupling constants are tabulated in ref.2, pp. 196-197, and later results arenow discussed relative to these. JHF in the system H*C*C*F shows a similardependence on dihedral angle to that 64 of JHH and longer-range interactionshave also been observed in saturated systems of favourable geometry.44All H,F interactions in vinyl fluoride (gem > trans > cis) have the samesign (assumed positive). l6 JHF in substituted benzenes shows similar(7.0 to 8.3 c/sec.).A A66R. A. Hoffman and S. Gronowitz, Arkiv Kemi, 1961, 16, 562.6 7 F. A. L. b e t , J . Chem. Phys., 1960, 32, 1274.68L. W. Reeves and K. 0. Strrmme, Canad. J . Chem., 1961, 39, 2318.6eR. J. Abraham and H. J. Bernstein, Canad. J . Chem., 1961, 39, 905.soG. S. Reddy and J. H. Goldstein, J .Phys. Chem., 1961, 65, 1539.62R. A. Hoffman and S. Gronowitz, Arkh Kemi, 1960, 15, 45.63 R. J. Tuite, H. R. Snyder, A. L. Porte, and H. S. Gutowsky, J . Phys. Chem.,1961, 65, 187; R. J. Tuite, A. D. Josey, and H. R. Snyder, J . kIr.neT. Chem. SOC., 1960,82, 4360.'j4R. J. Abraham and El. J. Bernstein, Canad. J . Chem., 1961, 39, 39.C. N. Banwell, Mol. Phys., 1961, 4, 26562 GENERAL AND PHYSICAL CHEMISTRYattenuation with increasing number of bonds, to that of JHH;59 a, 18 butwhereas the ortho- and meta-couplings have the same sign as the correspond-ing Jm,5 the para-H-F coupling is of different sign.@ J(31P-H) in thegrouping *CH,-P in phosphate esters and phosphonates is strongly dependenton substitution of alkyl groups, owing mainly to changes in the environmentof the methylene group;65, 66 correlation with the Taft o* resonance para-meter is discussed. Geminal and long-range €€-P coupling constants indiphosphine (186.5; 11.9 c/sec.) are of opposite sign to Jpp and JHH(108.2; -12 c/sec., assumed negati~e).~' JPF in a cyclic triphosphonitriliocompound 68 changes sign between F-P and F-P-N-P (934; 14 c/sec.: thelatter is tentatively assumed to be negative, together with -100 c/sec.for Jpp). J(l1B-l9F) in mixed boron halides 69 shows a very regular andrapid increase on progressive replacement of fluorine in boron trifluorideby less electronegative halogens (from 15 c/sec. in BF, to 108 c/sec. inBB'Br,) .A large number of J(13C-H) values have been obtained by Lauterburfrom the carbon-13 resonance spectra of aromatic compounds.70 These arediscussed in relation to the linear dependence reported earlier 1 upon thes-character of the carbon orbital involved in the bond, and upon the bondlength.Malinowski 71 has demonstrated that J(13C-H) in compoundsCHXYZ can be expressed as the sum of independent constants for eachsubstituent X, Y, and Z, to an internal consistency of &2 c/sec. over theexperimental range 127-206 c/sec. Holmes and Kaesz 7 2 report a similardependence of coupling between Sn and methyl protons in methyltin halidesupon the percentage s-character of the tin atomic orbital in the Sn-Cbond. Thus, a large increase in coupling observed in aqueous solution 72, 73is attributed to rehybridization of tin to give methyltin cations.Examples of long-range J(13CH),74 J(14NH),75 and JFF '13 have in eachcase demonstrated exceptions to the usual principle of attenuation withincreasing number of bonds.This is most pronounced in the last case, whereJ(H*C*C*F) in saturated compounds is nearly zero, whilst J(F*C*C*C*E') is10-17 c/sec. This is rationalized by supposing that most coupling occurs" directly through space," since there is a monotonic decrease in JFF withincreasing nuclear separation when the latter is averaged over all con-figurations. The very large values of JFF(gem) (up to 270.4 c/sec.) alsofit into this scheme. Analysis of the complex ethyl group spectra in com-pounds X(CH,*CH,),, where X is a single magnetically active nucleus andthe carbon atoms are numbered 1, 2 from X outwards, has revealed severaI86 G.D. Dudek, J . Chem. Phys., 1960, 33, 624.66G. Martin and G. M a d , Compt. rend., 1961, 253, 644. ,67 R. M. Lynden-Bell, Tram. Faraday SOC., 1961, 57, 888.68 M. L. Heffernm and R. F. M. White, J., 1961, 1382.60T. D. Coyle and F. G. A. Stone, J . Chem. Phys., 1960, 32, 1892.7OP. C. Lauterbur, J . Amer. Chem. SOC., 1961, 83, 1838; 1846.71E. R. Ivialinowski, J . Amer. Chem. SOC., 1961, 83, 4479.7% J. R. Rolmes and H. D. Kaesz, J . Amp. Chem. Soc., 1961, 83, 3903.73 J. J. Burke and P. C. Lauterbur, J . Amer. Chem. SOC., 1961, 83, 326.74 G. S. Karabatsos, J . Amer. Chem. SOC., 1961, 83, 1230.76 I. D. Kuntz, P. von R. Schleyer, and A. Allerhand, J. Chern. Phys., 1961, 35,76L. Petrakis and C.H. Sederholm, J . Chem. Phys., 1961, 35, 1243.1633BISHOP : NUCLEAR MAGNETIC RESONANCE 63interesting features 76, 77 (for other references, see footnotes in ref. 76). InPEt,, SnEt,, HgEt,, and PbEt,, Jx2 is considerably larger than Jxl, despitethe extra bond in the former interaction, and they are of different sign. Asimilar situation occurs in triethylthallium and mixed thallium alkyls, anddissimilar signs have been established 24 for TlEt, +. Each coupling increasesfairly regularly with increasing atomic number of X, Jxl and Jx2 rangingfrom 0.5 and 13.7 c/sec., respectively, in PEt, to 242.4 and 472-7 c/sec. inTlMe,Et. Anomalous coupling in these compounds has been ascribed totwo-electron terms in the Fermi contact interaction, but this has beencriticized by Stafford and Baldeschwieler.78 They find Jxl > Jx2, and ofsimilar sign, in ethyl fluoride (X = F); and suggest that interactions con-trary to this in the metal ethyls are due to d-electron-bonding effects.Chemical Shi€ts-Intramolecdm Eff ects.-Ramsey ’s general perturbationformula from electronic screening of a nucleus within a molecule includesdiamagnetic and paramagnetic contributions, the latter depending on excitedeigenstates.Use of these can be avoided if the problem is solved by approxi-mate (e.g. , variation) methods, but quantitative interpretation is stillrestricted to relatively simple molecules. Recent theoretical studies havebeen made of proton shielding in heteropolar diatomic molecules:79, 8oGroup VIB hydrides and the CH bond;sO acetylene,sl and molecular hydro-gen.gl, 82 Exact shielding in some two-electron atomic systems has alsobeen considered.83 In more complex systems, chemical shifts are best inter-preted in a semi-quantitat,ive manner as the sum of approximately inde-pendent contributions from local dia- and para-magnetic terms and long-range shielding by other atoms or groups within the molecule.2 This ismore directly related to the practice of nuclear magnetic resonance, sinceattention is then focused on the change of chemical shift within a relatedseries of compounds rather than on its absolute magnitude.The effect ofa substituent group upon the shielding of a remote nucleus may then inprinciple be resolved into two interactions: (1) Alteration of the local elec-tron distribution round the nucleus, e.g., by inductive or mesomeric electronrelay or by altering the state of hybridization. (2) Superposition of a smallmagnetic field due to its own electrons. This ‘‘ long-range ” effect averagesto zero upon rapid molecular orientation in a gas or liquid unless the groupis magnetically anisotropic (“ neighbour anisotropy effect ”).The smalllocal electron density round a proton renders this particularly sensitive tolong-range shielding effects.The most easily recognized case of magnetic anisotropy is the “ringcurrent ” in an aromatic ;z-electron system, which causes deshielding of thering protons l, and, to a smaller extent, of other substituents in the ring.Elvidge and Jackman84 have used this property to estimate aromatic77 P.T. Narasimhstn and M. T. Rogers, J . Chem. Phys., 1959, 31, 1431; 1961, 34,1049.78 S. L. Stafford and J. D. Baldeschwieler, J. Amer. Chem. SOC., 1961, 83, 4473.70 C. W. Kern and W. N. Lipscomb, Phys. Rev. Letters, 1961, 7, 19.soM. Fixman, J. Chern. Phys., 1961, 35, 679.Kurita and K. Ito, J. Amer. Chem. SOC., 1960, 82, 296.82S. K. Sinhe and A. Mukherji, J. Chern. Phys., 1960, 32, 1652.83R. E. Glick, J . Phys. Ghem., 1961, 65, 1871.84 J. A. Elvidge and L. M. Jackman, J . , 1961, 85964 GENERAL AND PHYSICAL CHEMISTRYcharacter in 2-pyridones. By comparing observed shifts with those pre-dicted for non-aromatic or fully aromatic structures, they infer 35 & 5%of aromatic character, as defined by the ability to sustain an induced ringcurrent, relative to benzene.By considering the differential ring-currenteffects upon different proton sites, Hoffman et ~ 1 . 8 ~ conclude that the lateralrings in 2,2’,2’’-terphenyl are roughly perpendicular to the central ringplane. A complete proton spectral analysis of the triphenylcarbonium ionindicates a skew orientation of the rings.86 Proton shifts also provide ameans of investigating the diamagnetic anisotropy of an individual bond,as has been discussed in detail by Jackman.31 When the induced magneticmoment of a bond is approximated to a point dipole, the calculated screen-ing effect upon a remote nucleus has an inverse cube dependence on distance,and an angular dependence, relative to the bond axis, of the form,3 cos2 8 - 1.Hence a magnetically anisotropic bond can cause an increaseor decrease in shielding according to the relative position of the nucleusconsidered. The high shielding of an acetylenic proton is due to the largesusceptibility of CIC along the bond axis. Proton shifts in acrylonitrilehave been interpreted in terms of a similar anisotropy of the CiN bond.87The anisotropy of the C-0 single bond has been estimated from proton shiftsin carbohydrates,88 and that of C=O demonstrated in cc-lumicol~hicine.~~The smaller anisotropy of the C-C bond has also been considered.90# 91Correlations of proton shifts with particular properties of substituentgroups are often uncertain on account of their sensitivity to long-rangeshielding and solvent effects.Unless the change in shielding within a seriesof compounds is dominated by one parameter, the interpretation is ambigu-ous. Spiesecke and Schneider 92-g4 have demonstrated recently that car-bon-13 spectra used in conjunction with proton shifts in organic compoundscan enable far more precise correlations to be made. Carbon-13 shifts areconsiderably larger, and more directly reflect substituent effects, than doproton shifts, and their solvent effects generally account for a smaller pro-portion of the total shift. The major disadvantage is the low naturalisotopic abundance of carbon-13 (-lyo) and ease of signal saturation, butthis can be offset by use of larger samples since lower effective field homo-geneity suEces to achieve similar proportional accuracy in shift measure-ments.Spiesecke and Schneider used isotopically enriched samples onlyfor dilution studies; and they employed a large rotating, spherical sample(1-5 ml.), with provision for an external standard, for the study of un-enriched samples. A flowing-sample method, with some threefold enhance-ment of signal strength, has also been described.95 Proton and carbon-1385R. A. Hoffman, P.-0. Kinell, and G. Bergstrom, Ark& Kemi, 1960, 15, 533.86R. S. Berry, R. Dehl, and W. G. Vaughan, J . Chern. Phys., 1961, 34, 1460.G. S. Reddy, J. H. Goldstein, and L. Mandell, J . Amer. Ghem. Xoc., 1961,83, 1300.88 R. W. Lenz and J. P. Heeschen, J . Polymer Sci., 1961, 51, 247.800. L. Chapman and H.G. Smith, J . Amer. Chem. SOC., 1961, 83, 3914.Qo J. I. Musher, J . Chem. Phys., 1961, 35, 1159.Q1 J. R. Cavanaugh and B. P. Dailey, J . Chem. Phys., 1961, 34, 1099.gaH. Spiesecke and W. G. Schneider, J. Chem. Phys., 1961, 35, 722.03H. Spiesecke and W. G. Schneider, J . Chem. Phys., 1961, 35, 731.D4H. Spiesecke and W. G. Schneider, Tetrahedron Letters, 1961, 468.O K s . Forsen and A. Rupprecht, J . Chem. Phys., 1960, 33, 1888BISHOP : NUCLEAR NAGNETIC RESONANCE 65shifts in methyl and ethyl compounds Me,X and Et,X show a linear correla-tion with the inductive effect of X (single atom or group) as measured by itselectronegativity, allowance being made for the " neighbour anisotropy "effect of the C-X bond.92 The latter causes systematic deviation of certainpoints (notably for X = C1, Br, I) from each of the linear plots, in the sensepredicted from the (3 cos2 8 - 1) angular dependence mentioned earlier :viz., to lower shielding in the cases of alH, PIH, and Pl3C, and to highershielding in the case of a-13C.Linear dependence of proton shift uponelectronegativity is reported also by Cavanaugh and DaileyYg1 who do not,however, find any significant neighbour anisotropy effect. The slopes ofboth proton and carbon-13 plots show greatest variation with X in methylcompounds, slightly less for a-CH, in ethyl compounds (ascribed to theslight difference in electronegativity between H and CH,), and much smallervariation in the p-position (CH, of ethyl group) owing to attenuation of theinductive effect.92 The latter causes a crossing of both proton and carbon-13lines corresponding to the a- and P-positions at an electronegativity value of-2.0, in agreement with the '' reversed " proton-shielding sequence foundin ethyl-metal compounds (see later).Combined study of proton andcarbon-13 spectra in monosubstituted benzenes, C,H,X, has led to a criticalreappraisal of substituent effects upon their chemical shifts. 93 The carbon-13spectrum has the added advantage that it includes also the atom of directattachment to X, where the large substituent effect was adequately explainedby inductive and neighbour anisotropy terms similar to those in the analo-gous a-position in ethyl compounds. These were smaller in the ortho-position (cf. /%position in ethyl compounds), where resonance contributionst o proton and carbon-13 shifts were also appreciable.Shifts in the rneta-position proved difficult to interpret, and covered a very small range forcarbon-13. In the para-position, inductive and anisotropy effects wereabsent. Proton and carbon-13 shifts were parallel, and probably domin-ated by changes in the n-electron density a t the carbon atom. Bothshowed a fairly linear correlation with the substituent Harnmett sigma-factor, although the precise significance of correlations with reactivity para-meters is criticized. In disubstituted benzenes, substituent effects uponthe proton shift in the metu- and para-positions are additive in dilutesolution. 96Linear dependence of both proton and carbon-13 shifts upon the localcarbon n-electron density, other factors being constant, has been confirmedby several workers in the case of homocyclic aromatic ions, where the n-elec-tron density is unambiguous.94, 9 7 p 989 99 Spiesecke and Schneider find thedisplacement of shielding to be +10-6 and +160 p.p.m.for proton andcarbon-13 respectively, per added electron a t the local carbon atom, in goodagreement with earlier values. These enable estimates of charge distribu-tion in other aromatic systems to be made from the observed shifts, withssP. Diehl, Helv. Chi'm. Acta, 1961, 44, 829.97 G. Fraenkel, R. E. Carter, A. McLachlan, and J. H. Richards, J . Amer. Chem.O 8 C . Maclean and E. L. Mackor, Mol. Phys., 1961, 4, 241.O0 P. C . Lauterbur, Tetruhedron Letters, 1961, 274.SOC., 1960, 82, 5846.66 GENERAL AND PHYSICAL CHEMISTRYallowance for other differential shielding effects if necessary, e.g., in azuleneY7Oand the pyridinium 100 and substituted carbonium lo1 ions.para-Substituent effects on fluorine-19 shifts are also parallel to thoseon proton and carbon-13, indicating that the same effect is dominant ineach case.93 Lauterbur 70 has also studied carbon-13 spectra of aromaticcompounds, and finds parallel variations in carbon-13 and fluorine-19 shiftsin both meta- and in para-positions ; fluorine shifts in ortho-substituted deri-vatives are altered by resonance interaction with the substituent.Sub-stituent effects on fluorine-19 shifts have also been discussed in relation toHammett factors and the polarity of the C-F bond.lO2-lO4 Correlationsof oxygen-17 shifts with structure in a large number of organic compoundshave been made by Diehl and his co-w0rliers.10~ Evidence for mesomericand inductive substituent effects in olefins is reviewed by Hoffman;s seealso ref.106.Proton andboron-11 shifts in borazole and substituted derivatives lo8 indicate appre-ciable electron transfer from nitrogen to boron, as would be required foraromaticity. Methylene and methyl proton shifts are approximately equalin B-ethyl derivatives. A cyclic bridge structure is confirmed for 2,4-di-methyltetraborane.109 Tin- 119 spectra in mixtures of tetrahalides SnX,(X = C1, Br, I) have enabled all possible mixed halide species, includingseveral previously unreported, to be detected.Chemical shifts cover arange of 1550 p.p.m. between tin tetrachloride and tetraiodide, and indicateapproximately additive contributions from each halogen atom. They areascribed mainly to changes in the local paramagnetic shielding term.73Some recent studies of molecular conformation have included an estimateof thermodynamic properties for interconversion of conformers of flexiblering systems, from the temperature dependence of the spectrum. The single,sharp proton line observed for cyclohexane at room temperature broadensinto a multiplet pattern, due to non-equivalence of axial and equatorialproton shielding, when the interconversion rate is diminished on cool-ing,110--113 from which an activation energy of 9-10 kcal./mole is found.Harris and Sheppard 112 find a substantial negative entropy of activationBoron-11 shifts have been measured by several workers.1071001. C.Smith and W. G. Schneider, Canad. J . Chem., 1961, 39, 1158.101C. Maclean and E. L. Mackor, J . Chem. Phys., 1961, 34, 2208.102 L. M. Iagupolskii, V. E. Bystrov, and E. Z. Utianskaia, Doklady Akad. Nauk103K. Ito, K. Inukai, and T. Isobe, Bull. Chem. SOC. Japan, 1960, 33, 315.104Y. Yonezawa, K. Fukui, H. Hato, H. Kitano, S. Hattori, and S. Matsuoka,loaH. A. Christ, P. Diehl, H. Schneider, and H. Dahn, Helv. Chim. Acta, 1961, 44,106G. S. Reddy and J. H. Goldstein, J . Amer. Chem. SOC., 1961, 83, 2045.107 T. D. Coyle, S. L. Stafford, and F. G. A. Stone, J., 1961, 3103; H.Landesmanl o s K. Ito, N. Watanabe, and M. Kubo, J . Chem. P h p . , 1960,32,947; 1961,34,1043.l o O I . Shapiro, R. E. Williams, and S. G. Gibbins, J . Phys. Chem., 1961, 65, 1061.1loF. R. Jensen, D. S. Noyce, C. H. Sederholm, and A. J. Berlin, J . Amer. Chem.lllL. W. Reeves and K. 0. S t r m e , Canad. J . Chem., 1960, 38, 1256; Trans.118 R. K. Harris and N. Sheppazd, Proc. Chem. SOC., 1961, 418.llS W. B. Monk and J. A. Dixon, J . Ame~. Chem. SOC., 1961, 83, 1671.S.S.S.R., 1960, 135, 377.Bull. Chem. Soc. Japan, 1961, 34, 707.865.and R. E. Williams, J . Amer. Chem. SOC., 1961, 83, 2663.SOC., 1960, 82, 1256.Faraduy SOC., 1961, 57, 390BISHOP : NUCLEAR MAGNETIC RESONANCE 67(-7.9 & 1 e.u.) in contrast with earlier assumption,l12 and similar to thatin perfluorocyclohexane. 114 The energy barrier is slightly increased onmono- or di-substitution,lll but a low value in the perfluoro-compound isattributed to torsional strain in the stable conformation.l14 The singlepeak of cis-decalin 2 remains sharp at -120",112, 113 confirming the highdegree of flexibility to internal rotation about the C-C bonds.trans-Perfluorodecalin gives distinct signals for equatorial and axial fluorinenuclei, the latter having a relative deshielding of 21-9 p.p.m., whilst rapidinterconversion again occurs in the cis-i~omer.1~~ Interconversion in the1 ,2-dioxan,l16, 117 1,3-dioxan,lls and 1,2-dithian 117 ring systems has alsobeen studied. Abraham and Bernstein have investigated rotational iso-merism in a substituted ethane.64The observation of the non-equivalence of the protons of an aliphaticmethylene group in several compounds is of particular interest.Finegold 119reported a duplication of the usual methylene quartet, with slightly differentchemical shifts and spacings, in the ethyl group resonance of certain diethylcompounds (e.g., diethyl sulphite), and inferred a difference in bonding ofthe methylene groups. This is disproved by later observations (a) that thesame effect occurs in similar compounds with only one ethyl group;120-122and (6) of further weak lines which permit analysis of the overall pattern asan ABC, or ABX, system.120 These were found also on re-examination ofthe diethyl sulphite spectrum,12, and a very recent analysis has shown thateach rnethylene proton is equally coupled to the methyl group, but thatthe interaction is of opposite sign to J,,, between them.39 The protonswithin the same methylene group are hence magnetically non-equivalent ,and this has been ascribed by Shafer et al.to an asymmetric conformationfavoured by restricted rotation. It has been pointed out, how-ever,12o, 121, 122, 124 that non-equivalence can persist in a molecule havingfree internal rotation if the symmetry of substitution is sufficiently low.It appears that non-equivalence of methylene protons should in theory occur,on free rotation, in any molecule in which the plane bisecting the HCHangle and normal to the interproton axis is not a plane of symmetry of themolecule as a whole for any conformation.The presence of an opticallyactive centre is a sufficient but not necessary condition for this, since non-equivalence of methylene protons in a group R should also occur in a com-pound RXR, possessing free internal rotation, such that replacement ofone R by a different group R' would induce optical activity. In practice,l14G. V. D. Tiers, Proc. Chem. Soc., 1960, 389.115 J. Homer and L. F. Thomas, Proc. Chern. SOC., 1961, 139.llsH. Friebolin and W. Maier, 2. Nabwforsch., 1961, 16a, 640.117 G. Claeson, G. Androes, and M. Calvin, J . dmsr. Chem. SOC., 1960, 82, 4428;llsN. Baggett, B. Dobinson, A. B. Foster, J. Homer, and L. F. Thomas, Chern.ll9H. Finegold, Proc. Chem. SOC., 1960, 283; J . Arner. Chem. SOC., 1960, 82, 2641.lZoP.R. Shafer, D. R. Davis, M. Vogel, K. Magarajan, and J. D. Roberts, Proc.lZ1 J. 8. Waugh and F. A. Cotton, J . Phys. Chem., 1961, 65, 662.lzsT. D. Coyle and F. G. A. Stone, J . Amer. Chm. SOC., 1961, 83, 4138.123 J. P. Pritchard and P. C. Lauterbur, J . Arner. Chem. SOC., 1961, 83, 2105.124 J. A. Pople, Mol. Phys., 1958, 1, 1.1961, 83, 4357.and Ind., 1961, 106.Nat. A d . Sci. U.S.A., 1961, 47, 4968 GENERAL AND PHYSICAL CHEMISTRYthe non-equivalence effect can be expected to diminish rapidly with increas-ing separation of the methylene group from the actual or potential centreof optical activity. It appears that all examples in the above referencescan be explained in this manner, without involving restricted rotation. Indiethyl sulphite, the non-equivalence would then depend upon the lack ofcoplanarity of the sulphur bonds.Non-equivalence of the CF, fluorine atomsin CF3*CF,-CFICl l 2 5 accords with this scheme. The non-equivalencereported in thiophosphonates , 66 and some of those in organophosphoruscompounds,126 can be similarly explained.The sensitivity of proton shifts to quite minor changes in molecularstructure has led to increasing application of nuclear magnetic resonance tostructural problems in classes of complex molecules of natural occurrence,and synthetic a,nalogues, where such changes can cause a profound modi-fication of their biological r61e. The success of this method depends largelyon the approximate additivity of long-range shielding effects, as demon-strated in the initial systematic study of steroid spectra by Shoolery a.ndRogers.1 Recent studies have been made of steroids,127, lZ8 bicyclic ter-penes,l29 triterpenes,l30 flavans,131 alkaloids,l32 polypeptides,133 b i ~ i n s , l ~ ~rotenoids,135 pyrimidines and nucleosides,l36 car~tenoids,~~~ and porphy-rins.l3* Abraham 139 has calculated the sign and magnitude of the ring-current effect on protons a t various sites in the porphyrin mo1ecule.l Lumryet ~ 1 .~ ~ 0 have studied the structure and denaturation of hzm-proteins bythe effect upon the proton relaxation time of added water. Balazs et aZ.lP1observed a broadening of the proton signal of water, without change in therelaxation time, in presence of deoxyribonucleic acid. An empiricallymodified form of Karplus's theory of proton spin coupling has been used toIZsL. M.Crapo and C. H. Sederholm, J . Chem. Phyls., 1960, 33, 1583.laa T. H. Siddall, C. A. Prohaska, and W. E. Shuler, Nature, 1961, 190, 903.IZ7 J. S. G. Cox, E. 0. Bishop, and R. E. Richards, J., 1960,5118; R. F. Ziircher andJ. Kalvoda, Helv. Chim. Acta, 1961, 44, 179, 186, 198; R. F. Ziircher, ibid., p. 1380.12sN. R. Trenner, B. H. Arison, D. Taub, and N. L. Wendler, Proc. Chem. SOC.,1961, 214.129 B. A. Arbuzov, Z. G. Isaeba, and Y. Y. Samitov, Doklady Akad. Nauk S.S.S.R.,1961, 13'7, 589.130 R. 0. Mumma, Diss. Abs., 1961, 21, 2485.I31M. M. Bokadia, B. R. Brown, P. L. Kolker, C. W. Love, J. Newbold, G. A.Somerfield, and T. M. Wood, J., 1961, 4663; J. W. Clerk-Lewis and L. M.Jackman,Proc. Chem. SOC., 1961, 165; E. J. Corey, E. M. Philbin, and T. S . Wheeler, TetrahedronLetters, 1961, 429.132 I. R. C. Bick, J. Harley-Mason, N. Sheppard, and M. J. Vernengo, J., 1961,1896.133 D. N. Shygorin, N. M. Pomeraatsev, and L. V. Sumin, Vysokomol. Soedineniya,134 M. S. Barber, A. Hardisson, L. M. Jackman, and B. C. L. Weedon, J., 1961, 1625.136L. Crombie and J. W. Lown, Proc. Chem. SOC., 1961, 299.136 S. Gronowitz and R. A. Hoffman, Arkiv Kemi, 1961,16, 459; J. P. Kokko, J. H.Goldstein, and L. Mandell, J . Amer. Chem. Soc., 1961, 83, 2909; C. D. Jardetzky, ibid.,p. 2919; R. U. Lemieux and M. Hoffer, Canad. J . Chem., 1961, 39, 110.137 J. B. Davis, L. 31. Jackman, P. T. Siddons, and B. C . L. Weedon, Proc. Chem.SOC., 1961, 261.E. D.Becker, R. B. Bradley, and C. J. Watson, J . Amer. Chem. Soc., 1961, 83,3743; R. J. Abraham, A. H. Jackson, and G. W. Kenner, J., 1961, 3468.139R. J. Abraham, MoZ. Phyn., 1961, 4, 145.laoR. Lumry, H. Matsumiya, F. A. Bovey, and A. Kowalsky, J . Phgls. Chem., 1961,65, 837.lgl E. A. Balazs, A. A. Bothner-By, and J. Gergely, J . MoZ. Biol., 1959, 1, 147.1961, 3, 560BISHOP : NUCLEAR MAGNETIC RESONANCE 69estimate bond angles within carbohydrate molecules in aqueous solution.The stereochemistry of reactions in the Kieb’s cycle has also been studied.lP2In organometallic compounds the shielding of a proton is increased ifit is close to the metal atom. The effect is very pronounced when thehydrogen atom is directly bonded to a metal, as in the carbonyl hydridesand related compo~nds,1~~ where displacements of the order of 20 p.p.m.to higher field, outside the usual range in diamagnetic compounds, areobserved. Smaller displacements are found in the vinyl- and ethyl-metalcompounds already discussed in relation to coupling constants.In thelatter, the methylene proton resonance is displaced to slightly higher fieldthan that of the methyl protons, contrary to the usual behaviour in ethylgroups. Olehic n-complexes with transition metals have been studied forstructural determination, in particular by Wilkinson, Pratt, and their co-workers,l4* who find proton spectra considerably Werent from those of theisolated hydrocarbons. Proton shifts are unusually widely spaced in a vinylgroup n-bonded to iron and a-bonded to it second iron atom in a carbonylderi~ative.1~5 Ally1 and substituted allyl complexes of PdCl appear to ben-bonded to palladium in deuterochloroform solution,146 but u-bonded indimethyl s~1phoxide.l~~ In the latter, all methylene protons in ,&substi-tuted allyl derivatives are equivalent. This phenomenon is observed alsoin allyl-lithium 41 in which a-bonding to the metal atom is again inferred.Equivalence of the methylene protons is ascribed to a rapid equilibriumX-CH,*CH:CH, f CH,:CH*CH,-X, as postulated earlier for allylmagne-sium br0mide.l Confirmation of the bridged structure of the dimer oftrimethylaluminium is given by the detection of distinct proton resonancesfrom the bridge and terminal methyl groups at low temperature.148 Protonshielding in tetramethyl compounds of Group IVB elements decreases pro-gressively on replacement of methyl groups by chl0rine.1~~ The structureof the carbon monoxide adduct of mercuric acetate has been determined.150The range of proton shifts in paramagnetic complexes of metal ions is verymuch greater, both to higher and lower shielding, than in diamagneticcompounds. This is attributed 151, 152 to a slight degree of electron spindelocalization transmitted from the paramagnetic metal atom to the ligandcarbon atoms.The direction of a proton shift is then determined by the142 0. Gawron, A. J. Glaid, and T. P. Fondy, J. Amer. Chem. SOC., 1961, 83, 3634.143 E. 0. Bishop, J. L. Down, P. R. Emtage, R.E. Richards, and G. Wilkinson, J.,1959, 2484 (references therein).144R. Burton, L. Pratt, and G. Wilkinson, J., 1961, 594; G. Winkhays and G.Wilkinson, ibid., p. 602; M. A. Bennett, L. Pratt, and G. Wilkinson, ibid., p. 2037;H. H. Hoehn, L. Pratt, K. F. Watterson, and G. Wilkinson, ibid., p. 2738; A. Davison,M. L. H. Green, and G. Wilkinson, ibid., p. 3172; D. Jones and G. Wilkinson, Chem.and Ind., 1961, 35, 1408.145 R. B. King, P. M. Treichel, and F. G. A. Stone, J. AWW. Chem. SOC., 1961, 83,3600.la6H. C. D e b and J. C. W. Chien, J. Amer. Chem. SOC., 1960, 82, 4429.147 J. C. W. Chien and H. C. D e b , Chem. and Id., 1961, 35, 745.14* N. Muller and D. E. Pritchard, J. Amer. Chem. SOC., 1960, 82, 248.lPDM. P. Brown and D. E. Webster, J.Phys. Chem., 1960, 64, 698.150 J. Halpern and S. F. A. Kettle, CheTn. and Ind., 1961, 35, 668.152R. E. Benson, D. R. Eaton, A. D. Josey, and W. D. Phillips, J. Amer. Chm.SOC., 1961, 83, 3714; W. D. Phillips and R. E. Benson, J. Chem. Phys., 1960, 33, 607.D. A. Levy and L. E. Orgel, MoZ. Phys., 1960, 3, 58370 GENERAL AND PHYSICAL CHEMISTRYsign of the spin density on the adjacent carbon atom. The wide range ofshifts (610 p.p.m.) in biscyclopentadienyl complexes has been studiedtheoretically by Levy and 0rgel.l5l Signals of protons are not appreciablybroadened if they are separated from the metal atom by several bonds,permitting nuclear spin-spin multiplets to be resolved and non-equivalentproton sites to be identified. Observed shifts in a series of nickel(@ chelateshave been used to deduce carbon n-electron spin densities, and it is con-firmed that these alternate in sign in conjugated systems.152Isotopic substitution is sometimes employed to simplify a complex spec-trum or to obtain spectral parameters in otherwise symmetrical molecules.To a good approximation, this does not affect other chemical shifts in themolecule, but the high precision of recent results has shown that isotopeshifts can often be detected across two bonds (for papers prior to 1960, seeref.153). In every case, substitution by the heavier isotope causes a dis-placement of the resonance of an adjacent nucleus to higher shielding(positive). Replacement of a hydrogen atom by deuterium causes a shiftof the order of +0.01 p.p.m.in the proton resonance of another hydrogenatom attached to the same ~ a r b o n , l ~ ~ - l ~ ~ and a somewhat higher value(+0.034 p.p.m.) was found in a~et0ne.l~' Slightly smaller effects are foundacross Si, P, and 0 in deuterated silane,26 phosphine,67 and ~ a t e r . 1 0 ~ Thedisplacement of fluorine resonance on deuterium substitution is muchlarger (+0.6 ~ . p . m . ) . l ~ ~ The sign and magnitude of these isotope effectsare explained by the smaller electrostatic deformation of electronic shieldingby the heavier isotope, due to the smaller zero-point vibration ampli-t ~ d e . 1 ~ ~ ~ 15', 158 The effect might reasonably be expected to diminish withincreasing atomic number of the isotopically varied element. Thus, carbonisotope effects upon 1H and 19F, on replacement 12C by 13C, are smaller thanthose on deuteration, and maintain approximately the same ratio.159Isotope effects of carbon-13 upon hydrogen directly bonded to it, have beenrecorded within the range from +0.0011 to 0.0045 ~ .p . m . l ~ ~ , 160 The largereffect on fluorine (+0-1 p.p.m. in 13C-F) has enabled its detection also acrosstwo bonds (W-C-F), where it is attenuated to +0-014 to 0-032 p.p.m.161A small silicon isotope effect upon fluorine has been recorded; replacementof silicon-28 by silicon-29 in hexfluorosilicate(1v) causes a shift of 0.004p.p .m.The principle of spin decoupling has been adapted recently to themeasurement of chemical-shift differences , particularly the very large shiftsbetween nuclei of dissimilar species, with greater accuracy than was hithertoattainable.162153G. V.D. Tiers, J . Inorg. Nuclear Chem., 1961, 16, 363.154M. Saunders, J. Plostnieks, P. S. Wharton, and H. H. Waaserman, J . Chem.lS5 H. Kusumoto, J. Itoh, K. Hirota, and J. Ueda, J . Phys. SOC. Japan, 1960,15,728.lS6 E. B. Whipple, W. E. Stewart, G. S. Reddy, and J. A. Goldstein, J . Chem. Phys.,lS7H. S. Gutowsky, J . Chem. Phys., 1959, 31, 1683.15*T. W. Marshall, MoZ. Phys., 1961, 4, 61.ls9G. V. D. Tiers, J . Phys. Chem., 1960, 64, 373.lsoH. Dreeskamp and E. Samann, 2. phys. Chem. (Prankfurt), 1961, 27, 136.161 G. V. D. Tiers, J . Phys. SOC. Japan, 1960, 15, 354.Phys., 1960, 32, 317.1961, 34, 2136.J. D. Baldeschwieler and E. W. Randall, Proc.Chem. SOC., 1961,304; S . L. ManatBISHOP : NUCLEAR MAGNETIC RESONANCE 71Chemical Shifts-Intermolecular Effects: Solvent Dependent Studies.-In this section are considered those effects which cause the magnetic shield-ing of nuclei to depend on their extramolecular environment. Ideally,such effects should be measured as departures from the chemical shifts inthe gas phase, a reasonable approximation to the condition of isolatedmolecules then being realized. In practice, the experimental difficulties aresuch that shifts have been recorded for only a few simple molecules in thegaseous state. Most studies of intermolecular effects are therefore madeby comparing chemical shifts in solution (“ solvent effects ”) as a functionof solvent, concentration, and temperature. Solvent-dependence of shifts isthen most conveniently referred to shift values extrapolated to infinitedilution in a nonpolar solvent having as nearly isotropic molecular proper-ties (in particular, shape, polarizability, and magnetic susceptibility) aspossible.It is further required that there shall be no specific associationbetween solute and solvent, the latter then being classified as “ inert ”;carbon tetrachloride and cyclohexane are commonly used. By this means,anisotropic interactions between solute molecules are eliminated, and thosebetween solute and solvent are minimized. The residual interactions areconsidered fist.A major cause of difference between the proton shielding in the gasphase and that of a nonpolar solute at infinite dilution in an inert, nonpolarsolvent is the bulk diamagnetic susceptibility of the latter.This effectdepends on the shape of the sample,2, 163 and, since it is not of chemicalinterest, some form of correction for it is applied. If chemical shiffs in acylindrical sample are measured relative to an external standard in a coaxialtube or sealed capillary, the correction can be calculated accurately as the‘‘ infinite cylinder ” condition.2 In this connexion, it has been pointed outrecently that the customary use of the bulk susceptibility for the puresolvent instead of the solution can lead to significant errors even in dilutesolution.16* Use of an internal standard provides an automatic compen-sation for the bulk susceptibility effect, but for comparison of shifts measuredin this way in different solvents it must be noted that the standard itself issubject to other shielding effects which cannot be calculated precisely.These are minimized in proton spectroscopy by use of tetramethylsilane asan internal standard.l This is soluble in all organic solvents but is virtuallyinsoluble in aqueous and ionic media, for which 2,2-dimethyl-Z-silapentane-5-sulphonate (D.S.S.) has been suggested as an alternative standard.165Bothner-By 166 has compared the proton shifts of nonpolar moleculesin the gaseous state with those at infinite dilution in nonpolar, or slightlypolar, inert solvents in cases where anisotropy effects of the solvent moleculesmay be neglected.The earlier observation by Evans is confirmed that, inevery case, the displacement of resonance to lower field on passing from theand D.D. Elleman, J . Amw. Chem. Soc., 1961, 83, 4095; J. A. Glasel, L. M. Jackman,and D. W. Turner. Proc. Chem. SOC.. 1961. 426.163A. D. BucLgham, T. Schaefir, and W. G. Schneider, J . Chenz. Phys., 1960,32. 1227.164R. J. Abraham, MoZ. Phys., 1961, 4, 369.leSG. V. D. Tiers aDd R. I. Coon, J . Org. Chem., 1961, 26, 2097.166 A. A. Bother-By, J . Mol. Spectroscopy, 1960, 5, 5272 UENERAL AND PHYSICAL CHEMISTRYgaseous state to solution is slightly in excess (0.1 p.p.m.) of that calculatedfrom the bulk-susceptibility correction. This is attributed mainly to thefluctuating electric field associated with van der Waals dispersion forcesbetween solute and solvent, with a further contribution from orbital dis-tortion if the solvent molecules contain a permanent dipole.Much largereffects in the same sense were observed by Evans 167 in the spectra offluorine-19 nuclei, where it is supposed that dispersion forces cause a signi-ficant increase in the local paramagnetic shielding term. This effectdiminishes with increase of temperature, as the average molecular separationincreases. Gordon and Dailey 168 have measured the proton shifts insimple nonpolar molecules as a function of pressure in the gaseous state,and of temperature in the pure liquid. The displacement to low field,again corrected for bulk diamagnetic susceptibility, is a similar, linear func-tion of density in both the gas and the liquid state.Turthermore, there isno measurable discontinuity on extrapolating the gas-phase values to theliquid region.Large proton shifts are produced when the solvent molecules are aniso-tropic both in shape and diamagnetic susceptibility. The extreme cases of“ rod-like ” and “ disc-like ’’ molecules are considered in particular byBuckingham et ~ 1 . 1 ~ ~ The most familiar example is the ring current of anaromatic molecule, already discussed in relation to intramolecular shieldinganomalies. Unlike the latter, the “ most effective configuration,” in whicha solute molecule can most closely approach a solvent molecule, is above orbelow the plane of the ring, where it is subject to an increased shielding.Conversely, in linear “ rod-like ” molecules with high magnetic susceptibilityalong the internuclear axis (e.g., acetylenes, carbon disulphide), a netdecrease in solute shielding is observed.Abraham 16* has made a carefulstudy of the solvent anisotropy effect by comparing the shifts, at lowconcentration, of a nonpolar solute in an anisotropic solvent with that of thesame solute in an isotropic solvent of identical bulk susceptibility. Theanisotropy shift for benzene is thereby found to be +0.42 p.p.m. (positivesign indicating a displacement to greater shielding) and, for carbon disulphide,-0.13 p.p.m. Theoretical estimates based on the van der Waals radiiare considered. Solvent anisotropy effects can be largely compensatedfor by use of an internal standard of similar molecular dimensions.I n the case of a polar solute, solvent effects can produce strong differen-tial shifts between protons in the same molecule.An important develop-ment has been the application of a reaction field theory by Buckingham 169to interpret these. The presence of a solute dipole moment causes a polari-zation of neighbouring solvent molecules to an extent determined by thedielectric constant of the medium. This in turn sets up an electric “ reac-tion field ” across the solute molecule, in the opposite direction to its dipole.That component E, along a bond X-H, linking a hydrogen atom to theremainder of the solute molecule, causes a change in the proton shielding bydistortion of the bonding-electron distribution, proportional to the first167D.F. Evans, J., 1960, 877.168s. Gordon and B. P. Dailey, J. Chern. Phys., 1961, 34, 1084.leSA. D. Buckingham, Canad. J. Chern., 1960, 38, 300BISHOP : NUCLEAR MAGNETIC RESONANCE 73power of E,, unless the proton is a t a molecular centre of inversion. Ac-cordingly, both magnitude and sense of the solvent shift depend upon theorientation of the bond X-H with respect to the solute dipole. This haspotential applications in relating spectral lines to proton locations withinthe molecules. Diehl and Freeman 17* have provided an elegant demonstra-tion of the conformation of paraldehyde, where the molecular dipole is per-pendicular to the ring plane. The axial hydrogen atoms have almost thefull reaction field along the C-H bond, and exhibit strong dependence ofproton shift upon solvent dielectric constant, whilst the equatorial methylgroups are scarcely affected.The polar groups are here well distributedover the molecule-it is pointed out that a localized polar group in a largemolecule may give the added complication of a non-uniform reaction field.This may also arise in the case of a molecule with no net dipole moment,but a large electronic quadrupole moment from opposed, well-separateddipoles, e.g., p-dinitroben~ene.~~~Further shielding effects arise if there is specific orientation betweensolute and solvent molecules due to association. Proton shifts are verysensitive to weak interactions which are often difficult t o detect by othermeans, and can be used to investigate them provided that due allowance ismade for the preceding solvent-shift mechanism~.16~, 171 Some examplesare now described.Schaefer and Schneider 1 7 2 have examined a seriesof para-disubstituted benzenes containing a strongly electron-attractinggroup X, in dilute solution in various solvents. They find a high-field dis-placement in benzene relative to an inert solvent, in excess of the solventanisotropy effect as measured by the shifts of p-xylene. The reaction field isexpected to be small, except in media of high dielectric constant, so theyinfer a weak hydrogen-bonding interaction-mainly with the proton metato the group X , since this shows a larger shift. Abraham 164 has recordedshifts for methyl iodide and iodoform in dilute solutions relative to aninternal standard, and finds a linear correlation with the calculated reactionfield except in certain aromatic solvents.The excessively high field shiftis here ascribed to complex formation, presumably of the. n-donor type.Thermodynamic properties of the complexes with toluene were found fromthe temperature dependence of the shifts: the values of AH (1.6, 1.3 kcal./mole) indicate a very weak interaction. Weak complexes involvingn-electron donation from an aromatic ring are also inferred betweenCHX, (X = C1, Br, I) and heteroaromatic compo~nds,~7~ amines and ben-~ e n e , l ~ ~ pyrrole and ~ y r i d i n e , l ~ ~ acetylenes and aromatic andbetween Al,Br, and benzene.177 Hatton and Richards 17* and Kowalewskiand Kowalewski 179 have noted that the proton resonances of the two methyl17*P.Diehl and R. Freeman, Mol. Phys., 1961, 4, 39.171R. E. Richards, Proc. Roy. Soc., 1960, A , 225, 72.172T. Schaefer and W. G. Schneider, J . Chem. Phys., 1960, 32, 1218.173Z. Pajek and F. Pellan, Compt. rend., 1960, 251, 79.174 C. Giessner-Prettri, Compt. rend., 1961, 252, 3238.176 J. A. Happe, J . Phys. Chem., 1961, 65, 72.J. V. Hatton and R. E. Richards, Trans. Paraday Soc., 1961, 57, 28.177D. Janjic, J. Delmau, B. Sum, and G. B6nt5, Compt. rend., 1960, 250, 2889.17* J. V. Hatton and R. E. Richards, Mol. Phys., 1960, 3, 253.179D. E. de Kowalewski and V. J. Kowalewski, Arkiv Kemi, 1961, 16, 37374 GENERAL AND PHYSICAL CHEMISTRYgroups in NN-dimethylformamide and NN-dimethylacetamide cross over ondilution in aromatic, but not in aliphatic, solvents.This provides goodevidence for complex formation in which the methyl group initially a t lowerfield is more directly over the centre of the aromatic ring. Differentialmethyl-group shifts are also reported on dilution of 16-methylcrotonic acidin benzene.lgO Lustig lS1 has applied the same principle to a study ofsyn-anti-isomerism in ketoximes. Two alkyl-group resonances are observedin solutions of symmetrical ketoximes in aromatic solvents, due to complexformation. Unsymmetrical monomethylketoximes again give two methylpeaks, one characteristic of each isomer.The very strong solvent-dependence of the shift of a proton involved inhydrogen bonding was recognized at an early stage.2 The displacementto low shielding on hydrogen bonding is in the sense expected from theelectrostatic nature of the bond, although the magnitude of the effect mustdepend in part upon a lowering of the local electron symmetry, with hin-drance to diamagnetic precession.171 Nuclear magnetic resonance dilutionstudies can provide valuable information about the type and strength ofhydrogen bonding involved.This is well illustrated by recent studies ofalcohols and phen01s.l~~ - l g 5 Dilution in an inert solvent causes progressivedisruption of intermolecular hydrogen bonds to an essentially monomericcondition at low concentration, with a high field displacement of the hydroxylproton resonance of the order of 5 p.p.m. Significantly smaller displace-ments occur in a solute able to form intramolecular hydrogen bonds, sincethis form will be increasingly favoured on dilution (e.g., in chloroethanols,ls2ortho-substituted phenols,l83~ 1859 186 and salicylaldehyde.ls7 Very smallsolvent shifts occur if hydrogen bonding is sterically hindered,lS2, lS8 forexample in triphenylmethanol where this is further conemed by tempera-ture independence.182 This is of help in deciding between molecular con-formations which differ in steric hindrance to hydrogen-bond formation, asin a recent study of ephedrines.l89 In hydroxy-compounds, limited corre-lation is obtained between dilution shifts and changes in intensity of theinfrared hydroxy-group stretching band.182 A better correlation is obtainedbetween hydroxyl proton and infrared shifts for intramolecularly hydrogen-bonded molecules in dilute solution, where the state of hydrogen bondingis more precisely defined.185 Proton resonance of the amino-group inaniline shows negligible displacement on dilution in carbon tetrachloride,suggesting virtual absence of hydrogen bonding, in agreement with infraredspectral data.174 In some of the association studies described in the pre-ceding paragraph, evidence was obtained for conventional hydrogen bonding180 S.Pujiwara, H. Shimizu, Y. Arata, and S. Akahori, Bull. Chem. SOC. Japan,lslE. Lustig, J . Phys. Chem., 1961, 65, 491.lszT. M. Connor and C. Reid, J . Mol. Spectroscopy, 1961, 7, 32.183M. Martin and M. Quilbery, Compt. rend., 1961, 252, 4151.l 8 4 I.Griinacher, Helv. Phys. Ada, 1961, 34, 272.185 L. W. Reeves, E. A. Allan, and K. 0. Strmnme, Canad. J . Chem., 1960,38, 1249.lsaI. Yamaguchi, Bull. Chem. Xoc. Japan, 1961, 34, 451.lS7I. Yamaguchi, Bull. Chem. SOC. Japan, 1961, 34, 353.ls8L. Ebersen and S. Forsbn, J . Phys. Chem., 1960, 64, 767.ls0 J. B. Hyne, Canad. J . Chem., 1960, 38, 135.1960, 33, 428BISHOP : NUCLEAR MAGNETIC RESONANCE 75in competition with n-interactions with aromatic systems. The former isindicated in the interaction of phenylacetylene and pyridine, from the lowfield displacement of the acetylenic proton resonance, and from the infraredspectrum.190 Mavel191 has derived theoretical concentration-dependencecurves for different kinds of complex formation and dissociation, and hasinvestigated the rate of exchange of the hydroxyl-group proton in alcohol-water mixtures.192 On dilution in chloroform, the exchange rate is loweredsuf3Eiciently to enable spin coupling to the alkyl group to be observed.Thisis attributed to hydrogen bonding between chloroform and the alcoholmolecule. l9The influence of solvent upon tautomeric equilibrium may be followedconveniently from changes in the relative intensity of the superimposedspectra of the individual tautomers.2 Several recent studies have beenreported.lg41 lg5 The enol form of acetoacetic ester is suppressed by smallamounts of strong bases.lg5Differential solvent shifts have been used in the interpretation of complexspectra.172 Pyridine may be used advantageously as a solvent for steroids,to separate methyl proton peaks which overlap in chloroform solution.lg6Protonation of weak bases in acid solution can be studied convenientlyby nuclear magnetic resonance, particularly with regard to the site of proto-nation and the rate of proton exchange. These effects are considered in thissection since, although not strictly intermolecular, they are strongly solventdependent. The question of 0- or N-protonation in amides has been anopen one for some time, but recent nuclear magnetic resonance studiesindicate strongly the preponderance of O-protonation, in agreement withother physicochemical methods. References to these are given by Katritzkyand Jones,197 who discuss the evidence in detail. The two methyl peaksof N-methyl-amides often coalesce in acid media.This is attributed tothe presence of a small amount of the N-protonated cation, which will havegreater freedom of internal rotation about the C-N bond. A similar con-clusion is inferred in the analogous case of pyridones.198 Co-ordination ofdimethylformamide to boron trichloride 199 and of dimethylpropionamideto iodine 2oo also occurs via the oxygen atom of the amide. The protonatedcations of water, ethyl alcohol, and acetone have been studied in solutionin hydrogen fluoride saturated with boron trifluoride.201 At low tempera-tures the exchange rate is slowed sufficiently to reveal the spectra of thelDoM. M. Kreevoy, H. B. Charman, and D. R. Vinard, J . Amer. Chem. SOC., 1961,lD1G. Mavel, J .Phys. et Radium, 1960, 21, 37.lD2G. Mavel, Compt. rend., 1960, 250, 1477; J . Phys. et Radium, 1960, 21, 731.lD3 J. Cantacuzhe, J. Gassier, Y . Lhermite, and M. Martin, C m p t . rend., 1960,250, 1474.lD4 G. 0. Dudek and R. H. Holm, J . Amer. Chem. SOC., 1961,83,2099,3914; R. Fillerand S. M. Naqvi, J . Org. Chem., 1961, 26, 2571; I. Griinacher, H. Suhr, A. Zenhaiisern,and H. Zollinger, Helv. Chim. Acta, 1961, 44, 313.lD6 C. Giessner-Prettri, Compt. rend., 1960, 250, 2547.lg6 G. Slomp and F. MacKellar, J . Amer. Chem. Soc., 1960, 82, 999.lS7A. R. Katritzky and R. A. Y. Jones, Chem. and Ind., 1961. 35, 722.lDeA. R. Katritzky and R. A. Y. Jones, PTOC. Chern. SOC., 1960, 313.lDD W. Gerrard, M. F. Lappert, H. Pyszora, and J. W. Wallace, J., 1960, 2144.%OoR. S.Drago and D. Bafus, J . Phys. Chem., 1961, 65, 1066.%OIC. Maclean and E. L. Mackor, J . Chem. Phyg., 1961, 34, 2207.83, 197876 GENERAL AND PHYSICAL CHEMISTRY+protonated forms. Proton shielding in OH is lower than that of OH inthe corresponding neutral hydroxy-compounds. Protonation of azulene intrifluoroacetic acid occurs in the five-membered ring, whilst the positivechange is accommodated in the seven-membered ring.202 At low tempera-ture, protonated mesitylene in hydrogen fluoride-boron trifluoride also showsa separate resonance peak due to ring methylene at the protonation site.It merges with that of the remaining ring protons, but not the hydrogenfluoride peak, at room temperature, indicating an unusual intramolecularhydrogen exchange between different ring sites.101Properties of electrolytes can also be studied by nuclear magneticresonance.1, 203 The temperature coefficient of dissociation of strong acidshas been measured by Hood and Reilly.20* Ionization of nitric acid issuppressed by addition of aluminium nitrate, owing to hydration of thecation and the common-ion effe~t.~O~ Jackson et aZ.206 have found that theoxygen-17 resonance of water in the hydration sphere of a cation can be dis-played as a separate peak by adding a small amount of paramagnetic co++ion, which displaces the resonance of unbound water molecules only. Thisis used to estimate hydration numbers. Proton shifts of water in solutionsof alkali halides vary linearly with concentration up to the point at whichwater molecules begin to be shared between two ions.207 The exchangerates of bromine- and iodine-containing complex ions in aqueous solutionhave been measured by Hertz from the width of the 79Br, 81Br, and 1291resonances.2o8 Rate constants for proton exchange in water 209 andaqueous solutions of ammonium and substituted ammonium ions 2lO havealso been measured from line-widths.Nuclear Magnetic Resonance of Solids.-Brief mention will be made ofsome of the recent applications of broad-line spectra of solids. A few studiesof the angular dependence of proton line shape and width in single, dia-magnetic crystals have been carried out to investigate the location of hydro-gen atoms, for example in thiourea 2 l 1 and Rochelle salt.212 Protonresonance of a single ice crystal is consistent with the Pauling hydrogen-bonding mode1.213 The inter-proton distance and orientation of watermolecules in a number of mono- and di-hydrated salts have been measuredby McGrath and Silvidi,214 and values given by previous workers are col-lected. The mean inter-proton distance in ten compounds is 1.595 A, fromwhich no departures outside the limit of experimental error were found.They infer that the structure and dimensions of water molecules of hydra-203 s. s. Danyluk and W. G. Schneider, J. Amer. Chern. SOC., 1960, 82, 997.203 J. E. Prue, Ann. Reports, 1960, 57, 80, Sect. (c).204G. C. Hood and C. A. Reilly, J. Chem. Phys., 1960, 32, 127.206 R. T. Axtermann; W. E. Shuler, and B. B. Murray, J. Phys. Chem., 1960,64, 57.206 J. A. Jackson, J. F. Lemons, and H. Taube, J. Chem. Phys., 1960, 32, 553.207 B. P., Fabricand and S. Goldberg, J. Chem. Phys., 1961, 34, 1624.2osH. G. Hertz, 2. Elektrochem., 1960, 64, 53; 1961, 65, 20, 36.209 S. Meiboom, J. Chem. Phys., 1961, 34, 375.2loM. J. Emerson, E. Grunwald, and R. A. Kromhout, J. Chem. Phys., 1960, 33,547; E. Grunwald, P. J. Karabatsos, R. A. Kromhout, and E. L. Purlee, ibid., p. 556.211.J. W. Emsley and J. A. S. Smith, Trans. Paraday SOC., 1961, 57, 893.212R. Rlinc and A. Prehesnik, J. Chem. Phys., 1960, 32, 387.213K. Kune and R. Hoshino, J. Phys. SOC. Japan, 1961, 16, 290.214 J. W. McGrath and A. A. Silvidi, J. Chem. Phys., 1961, 34, 322BISHOP : NUCLEAR MAGNETIC RESOPU’ANCE 77tion are not affected by their environment, and that the orientation adoptedis determined by the formation of hydrogen bopds with the nearest electro-negative atoms. The temperature-dependence of line-width in polycrystal-line materials provides information about internal rotations, since theonset of rotation will cause partial averaging-out of the direct dipole inter-action effect and a narrowing of the resonance line. findevidence for rotation of the cyclopentadiene rings in ferrocene, and this isslowed upon substitution in one or both rings. Peterlin and Pintar 216find that free rotation of the methyl group about the C-C axis in aceticacid is prevented in mono-substitution by chlorine. Dunell et aL217 showthat trichloroacetic and tribromoacetic acids are present as hydrogen-bonded dimers in the solid whereas acetic acid forms polymeric chains.The proton resonances of non-stoicheiometric, interstitial metal hydrideshave been studied over a wide range of temperature.21s, 219 A substantialdecrease in line-width on raising the temperature is ascribed to self-diffusionof hydrogen atoms, and the activation energies for this process are found.The lowest value found (2.4 kcal./mole) is that for PdH,.,,.219 Stalinskiet aZ.218 find that the activation energy in TiH, increases slightly withincreasing hydrogen content (x = 1.607 to 1.721). The observation of aproton chemical shift to high field by 0-01-0~032~0, in the opposite senseto the Knight shift in metals, is of interest. An interpretation is given interms of interaction between electrons localized on the hydrogen atom anddelocalized in.the metal conduction band. Bonding of hydrogen in thesecompounds is discussed. Investigation of polymers by proton resonancehas been reviewed by Sauer and W o o d ~ a r d . 2 ~ ~ ~Line shape of the boron-11 resonance signal in polycrystalline samplesdepends on the magnitude and symmetry of the local electric field gradient,which interacts with the nuclear quadrupole moment. In the case oftetrahedral bonding there is no net field gradient (e.g., tetrahydroborateion), but on progressive distortion to trigonal bonding the quadrupoleinteraction causes broadening and asymmetry of the boron-1 1 resonance.The state of co-ordination of boron in compounds of incompletely knownstructure has been investigated in this way.220Nuclear Spin Relaxation Times.-The rate of energy transfer betweena nuclear spin system and its environment is characterized by the spin-lattice relaxation time ( TI), also termed the “ longitudinal ’’ relaxation timesince it involves a change in the net nuclear magnetization vector componentalong H,. The rate of mutual energy transfer between two nuclei is charac-terized similarly by the spin-spin, or “ transverse,” relaxation time ( T2),215 C. N. Mulay, E. G. Rochow, E. 0. Stejskal, and N. E. Weliky, J . Inorg. NucEearChena., 1960, 16, 23.zlsA. Peterlin and M. Pintar, J . Chem. Phys, 1961, 34, 1730.217 B. A. Dunell, L. W. Reeves, and K. 0. Strermme, Trans. Faraday SOC., 1961, 57,218 B. Stalinski, C. K. Coogan, and H. S. Gutowsky, J . Chem. Phys., 1960, 33, 933;219 W. Spalthoff, 2. phys. Chent., 1961, 29, 258.21sa J. A. Sauer and A. F. Woodward, Rev. Mod. Phys., 1960, 32, 88.220 A. H. Bilver and P. J. Bray, J . Chem. Phys., 1960, 32, 288; A. H. Silver, ibid.,p. 959; P. J. Bray, J. 0. Edwards, J. G. O’Keefe, Y . F. ROSS, and I. Tatsuzaki, ibid.,1961, 35, 435.Mulay et372, 351.34, 119178 GENERAL AND PHYSICAL CHEMISTRYwhich involves a change in that component of the net nuclear magnetiza-tion vector which is at right-angles to H,. Only the first of these leads toa net change in spin energy, but both processes limit the lifetime of anucleus in a given spin state, and hence contribute to broadening of theresonance line. Methods used for their measurement are detailed else-where.2 In the case of a liquid, current theory requires that T, shall equalT2 when relaxation time is 222 A recent report by Bonera et aLZ2lconfirms this for a series of simple organic liquids within the limits ofexperimental accuracy, which are set by the T2 measurements. They finddifferent T, values for different groups within the same molecule in thecase of toluene, where the values for the methyl and aromatic protons are8 and 15 sec., respectively, in good agreement with previous measurements.Results by Powles and Cutler 222 are similar, but they find that, in benzene,T2 (11 sec.) is significantly shorter than T, (18 sec.). Possible theories forthis are discussed, and it is suggested that a fluctuation in nuclear spincoupling may be responsible. T, and T,in fluorobenzene (0.7 sec.) are appreciably shorter than in other aromaticsubstituted benzenes. The temperature dependence of T, in butyl alcoholshas been measured by Bernheim et aZ.223 This is linear except a t low tem-peratures, and the inferred activation energies for relaxation increase from3.9 to 7.3 kcal./mole in the sequence n < is0 < s < t-butyl alcohol. Thisdemonstrates that the shape of the molecule exerts a major effect upon themotions governing spin-lattice relaxation. The discrepancy between theobserved low-temperature minima and those calculated on the basis ofrandom molecular re-orientation indicates that rotation is restricted byhydrogen bonding. Spin-lattice relaxation by dipole-dipole interaction iscompounded of contributions from rotational and translational motions,and these are discussed theoretically by Mitchell and E i ~ n e r . ~ ~ ~ An experi-mental estimate of their relative contributions in benzene has been madeby dilution studies in deuteriobenzene.225 The ratio of T, values for protonsand fluorine-19 in fluoroform is over 100 : 1 in the gas phase,226 and it isinferred that spin-rotation interactions are here appreciable. Intermole-cular contributions to T, are sometimes T, and T, of protonsare considerably shortened by the presence of paramagnetic species, andLoembergen and Morgan 228 infer that they are then dominated by interac-tion of nuclear and unpaired electron spins.Both values increase on dilution.E. 0. B.E. 0. BISHOP. C. J. S. M. SIMFSON.T. L. COTTRELL. E. T. STEWART.R. E. RICHARDS. R. L. WILLIAMS.221 G. Bonera, L. Chiodi, G. Lanzi, and A. Rigamonti, Nuovo Cimento, 1960, 17, 198.222 J. F. Powles and D. Cutler, Nature, 1959, 184, 1123.223 R. A. Bernheim, J. D. Mackenzie, and R. C. Millikan, J . Chem. Phys., 1961,224R. W. Mitchell and M. Eisner, J . Chem. Phys., 1960, 23, 86.z2sM. Eisner and R. W. Mitchell, Bull. Arner. Phys. Soc., 1961, 6, 363.236 C. S. Johnson, J. S. Waugh, and J. N. Pinkerton, J . Chem. Phys., 1961,38, 1128.sz7F. A. Bovey, J . Chem. Phys., 1960, 32, 1877.22sN. Loembergen and L. 0. Morgan, J . Chem. Phys., 1961, 35, 842.34, 565

ISSN:0365-6217    

DOI:10.1039/AR9615800007

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

INORGANIC CHEMISTRY1. INTRODUCTIONTHE emphasis, noted in last year’s Report, on the chemistry of boron, silicon,phosphorus, and organometallic compounds has been maintained during1961, and these subjects again occupy a large proportion of the Report.There has, fortunately, been only a slight increase in the number of paperspublished in the inorganic field, and overall coverage has therefore againbeen possible. Since a report on crystallography is now to be publishedevery year, mention has been made of only a few structure determinationsof outstanding chemical interest.and organo-metallic compounds,2 the first volume of a revised edition of Brauer’sHandbook,3 and second editions of two textbooks on ~ a l e n c y . ~ A newabstract journal devoted to organometallics has a~peared.~ General ’reviews have been published on bond lengths and angles in inorganic com-pounds,6 valency-bond structures and hybridization in compounds of first-row elements,’ the structures of eight-co-ordination compounds, * thedimerization of inorganic free radical^,^ synthetic gemstones, lo and nuclearfission.l1New books include A.C.S. Monographs on perchloratesMany other reviews are mentioned elsewhere.D. W. A. S.A. G. S.2. TYPICAL ELEMENTSGroup 1.-The alkali-metal polyfluorides, reported to be obtained bythe action of fluorine on alkali-metal chlorides, have been shown to be fluoro-chlorites of formula MClF,, analogous to the well-known fluorobromites ;they react violently with water, and are decomposed by heat into the metalfluoride and chlorine trifluoride.A mass-spectrometric study of ethyl-lithium vapour suggests that the1 “ Perchlorates,” ed.V. Sauchelli, Reinhold Publ. Corp., New York, 1960.“ Organometallic Chemistry,” ed. H. Zeiss, Reinhold Publ. Corp., New York,1960.“ Handbuch der Praparativen anorganischen Chemie,” ed. G. Brauer, FerdinandEnke Verlag, Stuttgart, Vol. I, 1960.4 E. Cartmell and G. W. A. Fowles, “ Valency and Molecular Structure,” Butter-worths, London, 2nd edn., 1961; C. A. Coulson, “ Valence,” Oxford Univ. Press, 2ndedn., 1961.5 “ Organometallic Compounds,” Translation and Tech. Infn. Services, London.6R. J. Gillespie, J . Amer. Chem. SOC., 1960, 82, 5978; Canad. J . Chem., 1961,* R’. J. Gillespie, Canad. J . Chem., 1961, 39, 2336.See also, however, J. L. Hoard,9M. Green and J. W. Linnett, J., 1960, 4959.39, 318.G. L. Glen, and J. V. Silverton, J . Amer. Chem. Xoc., 1961, 83, 4293.H. A. Bent, Chem. Rev., 1961, 61, 275.loE. A. D. White, Quart. Rev., 1961, 15, 1.l1 G. N. Walton, Quart. Rev., 1961, 15, 71.____.______ _ _ -~IH. Bode and E. Klesper, 2. anorg. Chem., 1951, 267, 97.2L. B. Asprey, J. L. Margrave, and M. E. Silverthorn, J . Amer. Chem. SOC., 1961,83, 295580 INORGANIC CHEMISTRYpredominant species are the hexamer and tetramer;3 it seems probable thatthe bonding in these compounds is of the multicentre electron-deficient typethat occurs in beryllium and aluminium a l k y l ~ . ~ Potassium reacts withcyclo-octatetraene in tetrahydrofuran to yield an unstable white compoundK2CsHs,THF ; physicochemical evidence indicates the presence of a planarCsHs2- ion.The thermal stabilities of addition compounds of lithium boro-hydride and ethers decrease along the series tetrabydrofuran > dimethylether > diethyl ether > di-isopropyl ether, which suggests that the strengthof the ether as an electron-donor is the most important factor in determiningstability. Evidence has been obtained for the existence of an adduct con-taining two molecules of tetrahydrofuran. The various compounds formedwhen alkali metals dissolve in methanol have been thoroughly examined:lithium forms only LiOMe (which has a structure similar to that of lithiumhydroxide) ; sodium forms NaOMe and NaOMe,SMeOH ; potassium formsKOMe, KOMe,MeOH, and KOMe,3MeOH.' Other systems investigatedinclude those of potassium, rubidium or caesium, and antimony or bismuth,and pot assium-arsenic .Group II.-Basic beryllium nitrate, Be40(N03)s, is obtained as a volatileproduct of the decomposition of the anhydrous nitrate; this has been madeby the action of dinitrogen tetroxide on beryllium chloride in the presenceof ethyl acetate and subsequent decomposition of the adduct Be(NO3),,2N,O4.The similarity of its formula to that of the well-known basic acetate suggeststhat the nitrate groups are acting as bidentate ligand~.~ Several colouredcomplexes of 2,2'-bipyridyl or o-phenanthroline and beryllium alkyls orhalides have been described, and it is suggested that the colour arises fromthe transfer of an electron from the beryllium-containing molecule to thelowest unoccupied orbital of the organic compound; in the series bipyBeX,,where X = C1, Br, or I, decrease in the electronegative character of Xresults in an increase in the extinction coefficient.1° Macrocyclic 8-di-carbonyl beryllium chelates have been made by heating the correspondinglow molecular weight polymers; they inturn polymerise, on being heated abovetheir melting points, with the production oflinear chelate polymers, such as (l), whichare soluble in aromatic solvents.11Diethylmagnesium made from pure mag-nesium reacts with diborane to form the compounds MgH,(BH,Et), andMgH,Et(BHEt), for which hydrogen-bridged structures are suggested.l2Organomagnesium halides have been made in hydrocarbon media by re-& ; ; d o g - \ 0('I3 J.Berkowitz, D. A. Bafus, and T. L. Brown, J . Phys. Chem., 1961, 65, 1380.4 R. West and W. Glaze, J . Amer. Chem. SOC., 1961, 83, 3580.5H. P. Fritz and H. Keller, 2. Naturforsch., 1961, 16b, 231.6 T . L. Kolski and G. W. Schaeffer, J . Phys. Chem., 1960, 64, 1696.7P. J. Wheatley, J . , 1960, 4270.8G. Gnutzmann and W. Klemm, 2. anorg. Chem., 1961, 309, 181; F. W. Dornand W. Klemm, ibid., p. 189; F. W. Dorn, W. Klemm, and S. Lohmeyer, ibid., p. 204.9 C. C. Addison and A. Walker, Proc. Chem. SOC., 1961, 242.10G. E. Coates and S. I. E. Green, PTOC. Chem. SOC., 1961, 376.11R. W. Kluiber and J. W. Lewis, J. Amer. Chem. SOC., 1960, 82, 5777.14 R. Bauer, 2.Naturforsch., 1961, 16b, 557SHARPE: TYPICAL ELEMENTS 81actions between various alkyl and aryl halides and magnesium in theabsence of the usual ethereal catalysts, and it is noteworthy that theirempirical formulz approximate not to RMgX but to R,Mg2X; they maycontain both alkyl and halogen bridges. Unlike ethereal Grignard reagents,they react with titanium halides to form olefinpolymerisation catalysts. l3The chemistry of the alkaline-earth metal phosphates has been reviewed.14Cyclopentadienyl derivatives of these metals have been obtained by theaction of cyclopentadiene on the hydrides at 260-400" or, in the case ofcalcium and strontium, on the metals in the presence of tetrahydrofuranor dimethylformamide.15Group 1II.-Boron. Two new methods for the preparation of diboranehave been described: good yields are obtained by heating stannous chloridewith sodium borohydride a t 200-250°,16 and hydrogenation of alkylboronstakes place in the presence of the usual catalysts a t 150O.l' The success ofthe latter process depends upon the action of the hydrogen present at highpressure in inhibiting the pyrolysis of diborane.The exchange of deuteriumbetween diborane and dimethylaminodiborane is of order 0.5 and 1 withrespect to these reactants, suggesting the participation of borane radicalsin the rate-determining stage.l*Sodium borohydride can be made by the interaction of sodium, hydrogen,and dehydrated borax in the presence of quartz sand;l9 three reviews of thereactions of borohydrides have been published.19-21 Sodium borohydrideis not attacked by bromine in hexane or benzene at 80°, but iodine reacts,forming boron tri-iodide, sodium iodide, hydrogen iodide, and hydrogen ;with hydrogen iodide, sodium iodide, diborane, and hydrogen result.22Thiocyanogen in ether reacts with lithium or sodium borohydride to forma compound of formula MBH(NCS)3.23The '' diammoniate " of tetraborane has been re-examined and shownto have the structure [H2B(NH3),][B3H,],24 and the tetramethylammoniumsalt containing the same anion has been obtained by the sequence 25Et,S MeOH Me,N.OH MeOHB,,H,, + (Et,S),B,,H,, + Et,SB,H,, - Me,NB,H,, __+ Me,NB,H,.Tetraborane reacts with pyridiiie at 0" to form BH3,py and B2H4,py.26The passage of the hydride B,H, in an atmosphere of hydrogen through13D.Bryce-Smith and G. F. Cox, J . , 1961, 1175.l*R. TV. Murray and M. A. Aia, Chem. Rev., 1961, 61, 433.15E. 0. Fischer and G. Stolzle, Ber., 1961, 94, 2187.l6 W. Jeffers, Chem. and Ind., 1961, 431.l7 R. Klein, A. Bliss, L. Schoen, and H. G. Nadeau, J . Amer. Chem. SOC., 1961,l8 J. S. Rigden and W. S . Koski, J. Amer. Chem. SOC., 1961, 83, 552.l9 F. Schubert and K. Lang, Angew. Chem., 1960, 72, 994.zoH. Noth, Angew. Chem., 1961, 73, 371.21 H. C. Brown, Tetrahedron, 1961, 12, 117.2zF. Klanberg and H. W. Kohlschutter, Ber., 1961, 94, 786.2sF. Klanberg, Proc. Chem. SOC., 1961, 203.24 G. Kodama and R. W. Parry, J . Amer. Chem. SOC., 1960, 82, 6250.26V. I. Mikheeva and V. Y. Markina, Zhur. neorg. Khim., 1960, 5, 1977 [963].*83, 4131.B.M. Graybill, J. K. Ruff, and M. F. Hawthorne, J . Amer. Chem. SOC., 1961, 83,2669.*Page numbers in brackets refer to the English translation82 INORGANIC CHEMISTRYan electric glow discharge between copper electrodes results in the formationof a new hydride, B10H16, in which two B,H, units (each consisting of apentagonal pyramid of five boron atoms, with those in the basal planejoined by hydrogen bridges and carrying one unbridged hydrogen atom)joined by a B-B bond.,, Many new amine-substituted decaboranes havebeen reported.2s Other substitution products of the same hydride includethose in which the donor group is a sulphide, sulphoxide, phosphine oxide,amide, or thioamide ; 29 displacement reactions 30 show that the strengthof the bonding increases along the series Me,S < MeCN < Et,N*CN <HCO-NlVte, = AcNMe, < Et3N = py = Ph3P.Diborane, tetraborane, and decaborane react with sodium cyanideto form substituted borohydrides Na(H,BCNBH,), NaB,H,.CN, andNaBloHl,-CN, generally isolated as etherates. Diborane and ammoniumcyanide initially form a substituted borohydride, but hydrogen is then lostand the final product is the ammonia adduct of B,H5*CN.31 Friedel-Crafts methylation of decaborane takes place mainly in the 2- and 4-positions,to a less extent in the 1- and 3-positions; in nucleophilic attack by lithiumalkyls, however, 6-substitution predominates.When decaborane reactswith Grignard reagents two processes take place, formation of the deca-boranyl Grignard reagent and the hydrocarbon and, to a smaller extent,formation of the 6-aIkyl-de~aborane.~~The compound NaBEt, is obtained by the interaction of ethylsodiumand triethylboron, or ethyl chloride and triethylboron in the presence ofsodium, or ethylene and the sodium salt NaBHEt,; it is stable towardswater but is decomposed by acids; several homologues have also been pre-pared.33 Alkylboranes can be made from aluminium alkyls, lithium boro-hydride, and hydrogen halides or boron halides at atmospheric pressure andtemperatures in the range 100-175", and also by the action of hydrogenunder pressure on boron trialkyls (e.g., 2BR, + 5H, +P B,H5R + 5RH).34When B,B,Me, reacts with ethylene at room temperature the main pro-ducts are Me,BEt, MeBEt,, and BMe,; with 3,3,3-trifluoropropene the mainproducts are trimethylboron and dimethyl-3,3,3-trifluoropropylboron,(CF,*CH2*CH2-BMe,).35 I n the presence of 2,6-lutidine, 1 -alkylpenta-boranes-9 rearrange to the 2-alkyl compounds.36 Mass spectra of somelower boron alkyls have been reported.37The compound N,H,,BH, is obtained by the action of hydrazinium27 R. Grimes, F. E. Wang, R. Lewh, and W. N. Lipscomb, Proc. Nut. Acad. Sci.,28 H. C. Beachell and B. F. Dietrich, J . Amer. Chem. SOC., 1961, 83, 1347; B. M.SQ W. H. Knoth and E. L. Muetterties, J . Inorg. Nuclear Chem., 1961, 20, 66.30R. J. Pace, J. Williams, and R. L. Williams, J., 1961, 2196.31V. D. Aftandilian, H. C. Miller, and E. L. Muetterties, J . Amer. Chem.SOC.,32R. L. Williams, I. Dunstan, and N. J. Blay, J., 1960, 5006, 5012, 5016.33 J. B. Honeycutt and J. R. Riddle, J . Amer. Chem. Xoc., 1961, 83, 369.34 L. H. Long and A. C . Sanhueze, Chem. and Ind., 1961, 588; R. Koster, G. Bruno,35 J. M. Birchall, R. N. Haszeldine, and J. F. Marsh, Chern. and Ind., 1961, 1080.36T. P. Onak, J . Amer. Chem. Xoc., 1961, 83, 2584.37 D. Henneberg, H. Damen, and R. Koster, Annalen, 1961, 640, 52.U.S.A., 1961, 47, 996.Graybill and M. F. Hawthorne, ibid., p. 2673.1961, 83, 2471.and P. Binger, Annalen, 1961, 644, 1SHARPE: TYPICAL ELEMENTS 83sulphate on sodium borohydride in tetrahydrofuran ; its pyrolysis undercontrolled conditions leads to the formation of H,B-NH*NH*BH,, obtainedits a crystalline polymer stable to water and acids.38 Hydrazine and tri-methylboron give 1 : 2 (unstable) and 1 : 1 (stable) adducts. At 25" di-borane displaces trimethylboron from the 1 : 1 compound, forming 1,l-di-methyldiborane, hydrogen, ethylene, and a heterogeneous solid.39 At 100"hydrazine and tetra-alkyldiboranes react according to the equation 4OB,H,R4 +- K2H4 --+ R,B*NH*NH.BR, + 2H,.Several aminodiarylboranes , Ar,B*NR,, have been prepared by reac-tions such as2Ph2BC1 + SPU'H, + BNEt, + (Ph,B*NH,), + 2Et,NHClAr,BCl + LiNR, + Ar,B*NR, + LiCl2ArMgBr + Cl,B.NR, + Ar2B*NR, + MgC1, + MgBr,.When R = H the compound is dimeric in benzene or nitrobenzene; theother compounds are monomeric in both solvents.The correspondingphosphino- and arsino-boranes can be obtained by analogous routes; theyare much more stable to hydrolysis than the amino-~ompounds.~1 A com-parative study of the proton magnetic resonance spectra of compounds suchas Me,B*NMePh, PhClBONMe,, and PhB(NMe,), suggests that p , - p , B-Nbonding is largely responsible for the hindered rotation about the B-N bondin these substances. 4 2 Tri( alkylamino) boranes, di(alkylamino)arylboranes,and borazoles undergo a general transaminafion reaction with primary orsecondary mono- and poly-amines : 43)R*NR, + HNR', + )B-NR', + HNR,.Tetrakisdimethylaminodiborane, (Me,N),B*B(NMe,),, has been obtained bythe interaction of (Me,N),BCl and highly dispersed molten sodium ; it reactswith many amines in the same way as do monoborane derivatives, and isconverted by alcohols or phenols into esters of hypoboric acid.44The chemistry of borazoles has been reviewed with special reference toRussian work.45 Some exchange reactions of borazole have been studied:ND,, DC1, and DCN exchange deuterium for hydrogen attached to nitrogena t a rate comparable with the rate of addition of these compounds; D,, B,D,,and NaBD, exchange deuterium for hydrogen attached to boron; no ex-change is observed with D,S, C,D,, or PD,.46 Hexahydroborazole has beenprepared by reduction of the hydrogen chloride adduct of borazole with38 J.Goubeau and E. Ricker, 2. anorg. Chem., 1961, 310, 123.39 W. G. Paterson and M. Onyszchuk, Canad. J . Chem., 1961, 39, 2324.40H. Noth, 2. Naturforsch., 1961, 16b, 471.41G. E. Coates and J.G. Livingstone, J., 1961, 1000.4aG. E. Ryschkewitsch, W. S. Brey, and A. Saji, J . Amer. Chem. SOC., 1961, 83,1010; P. A. Barfield, M. F. Lappert, and J. Lee, Proc. Chem. SOC., 1961, 421.43 W. D. English, A. L. McCloskey, and H. Steinberg, J . Amer. Chem. SOC., 1961,83, 2122; H. Noth, 2. Naturforsch., 1961, 16b, 470.44 B. J. Brotherton, A. L. McCloskey, L. L. Petterson, and H. Steinberg, J . Amer.Chem. SOC., 1960, 82, 6242; B. J. Brotherton, A. L. McCloskey, J. L. Boom, and H. M.Manasevit, ibid., p. 6245; H. Noth and W. Meister, Ber., 1961, 94, 609.46B. M. Mikhailov, Uspelchi Khim., 1960, 29, 972 [459].46 G. H. Dahl and R. Schaeffer, J . Amer. Chem. SOC., 1961, 83, 303484 IN 0 RG AN1 C CHE iM IS TR Ysodium borohydride; it is a non-volatile solid stable in the ordinary atmo-sphere, and is insoluble in benzene but soluble in several more polar organicsolvents.47 Condensation of borazole by pyrolytic dehydrogenation leadsto the formation of B5N,H8 (m.p. 27-30') and B6N,Hl, (m.p. 59-60"),the B-N analogues of naphthalene and biphenyl, and several other com-pounds. 48BBB-Trialkylborazoles can be made by the interaction of trimethyl-amine, alkylboranes, and excess of ammonia in diethylene glycol dimethylether a t 100-150"; the reaction is catalysed by ammonium chloride.49Hexamethylborazole forms a n-complex with tetracyanoethylene. 5O Con-ditions for the convenient large-scale laboratory preparation of BBB-tri-chloroborazole from boron trichloride and ammonium chloride have beendescribed ; this compound is converted into cyano- and thiocyanato-com-pounds by treatment with silver cyanide and potassium thiocyanate, andindications of the formation of nitro- and nitrato-compounds have beenobtained in a study of its reactions with silver nitrite and nitrate.51 Borontrichloride, phosphoryl chloride, alcohols, and NN-dimethylhydrazine reactwith B-aminoborazoles to give B-chloro-, B-alkoxy-, and B-hydrazino-compounds. BBB-Triamino-NNN-triethylborazole, [*B(NH,)*NEt*],, isobtained in low yield when BBB-trichloro-NNN-triethylborazole reactswith ammonia in benzene.All reactants must be of high purity; the pro-duct, though not especially unstable towards heat, is highly sensitive tohydrolytic de~omposition.~2 Several unsymmetrically substituted bor-azoles have been obtained by displacement reactions, e.g., BBB-trisdiethyl-a,mino-NNN-triethylborazole reacts with ethylamine with displacement ofone diethylamino-gro~p.~3Boron trifluoride and hydrazine form a 1 : 1 adduct, but in tetrahydro-furan the 2 : 1 compound is also obtained; thermal decomposition of theformer yields nitrogen, ammonia, ammonium fluoroborate, and boronnitride,5* The compound CF,*BF, has been obtained by the action of borontrifluoride on the product of the interaction of potassium di-n-butylboronand trifluoroiodomethane in ether, and also (as an etherate) by the actionof CF3*SC1 on diborane. Trimethylamine displaces the ether, but borontrifluoride does not react, indicating that, as would be expected, CF,*BP2is a stronger Lewis acid than BF3.55 The perfluorovinyl compounds(CF,:CF)BF,, CF,:CF*BCl,, (CF,:CF),BCl, and (CF,:CF),B have been obtainedby the use of dimethylbisperfluorovinyltin for the introduction of theorganic groups.56 The compound formerly described as Et,NH*BP, is47G.H. Dahl and R. Schaeffer, J . Amer. Chem. SOC., 1961, 83, 3032.48A. W. Laubengayer, P. C. Moews, and R. F. Porter, J . Amer. Chem. Soc., 1961,49M. F. Hawthorne, J . Amer. Chem. Soc., 1961, 83, 831. 833.50N. G. S. Champion, R. Foster, and R. K. Rlackie, J . , 1961, 5060.51 G. L. Brennan, G. H. Dahl, and R. Schaeffer, J . Amer. Chem. SOC., 1960, 82,52 I<. Niedenzu, D. H. Harrelson, and J. W. Dawson, Ber., 1961, 94, 671.53M. F. Lappert and M. K. Majumdar, Proc. Chem.Soc., 1961, 425.54 W. G. Paterson and M. Onyszchuk, Canad. J . Chem., 1961, 39, 986.55T. D. Parsons, E. D. Baker, A. B. Burg, and G. L. Juvinall, J . Amer. Chem.6 6 s . L. Stafford and F. G. A. Stone, J . Amer. Chm. SOC., 1960, 82, 6238.83, 1337.6248.SOC., 1961, 83, 250SHARPE: TYPICAL ELEMENTS 85actually the salt Et,NH,+ BF4-; the adduct has now been described andshown to resemble the numerous other compounds of boron trifluoride withamines.57 The oxfluoride B303F3 has been shown to have a cyclicstructure. 58Diboron tetrachloride can be obtained by the action of boron trichlorideon the oxide (BO), at 230°;59 details of its reactions with amines, nitriles,ethylene oxide, oxygen, and hydrazine have been described. With nitricoxide, a 1 : 1 adduct is formed; this decomposes at -40°, yielding a com-pound B,(NO),,BCI, from which the boron trichloride can be removed bypumping or by the action of trimethylamine; the solid residue of composi-tion B2N303 is thermally stable.60 With naphthalene, the compoundCl,H,,2B2C1,, which appears to contain four BCl, groups added to the samering, is produced; with benzene, an unstable product which quickly decom-poses to form phenylboron dichloride is obtained.s1 Evidence for theexistence of the B2ClG2- ion has been obtained in the conductimetric titra-tion of diboron tetrachloride in liquid hydrogen chloride with tetramethyl-ammonium chloride and the isolation of the compound (Me4N),B,Cl,.62Tetra-chloro- and -brorno-borates of diazonium and other large organiccations have been described.63Alkali and alkaline-earth metals and their nitrides have been found tobe effective catalysts for the conversion of hexagonal boron nitride intothe cubic form.64 When boron nitride is heated with lithium or calciumnitride or barium amide a t 700-1000 O , ternary nitrides Li3BN,, Ca3B,N4,and Ba3B2N4 are obtained ; these compounds are decomposed by wateror acids, and their infrared spectra suggest that they contain N=B=N3-ions.65The hypoborate NaOBH,, which Stock reported to be formed by theaction of diborane on aqueous alkali, appears to have consisted mainly ofthe borohydride.s6 Hydrated sodium peroxoborate has been shown to con-tain two peroxo-bridges per anion, and its formula should be writtenNa2[B2( %(OH)41,6H20-67Aluminium. The preparation of lithium and sodium aluminiumhydrides from metal hydrides, aluminium, and hydrogen in tetrahydrofuranhas been described, and the properties and uses of these compounds havebeen reviewed.68 Lithium aluminium hydride in benzene or ether reacts571.G. Ryss and D. B. Donskaya, Zhur. neorg. Khim., 1960, 5 , 2251 [1090].68H. D. Fischer, W. J. Lehmann, and I. Shapiro, J. Chem. Phys., 1961, 65,59 A. L. McCloskey, J. L. Boone, and R. J. Brotherton, J. Amer. Chem. SOC., 1961,6 o A. K. Holliday and A. G. Massey, J., 1961, 1893, 3348; J . Inorg. Nuclear Chem.,61 W. B. Fox and T. Wartik, J. Amer. Chem. SOC., 1961, 83, 498.62A. K. Holliday, M. E. Peach, and T. C. Waddington, Proc. Chem. SOC., 1961,63 K.M. Harman and A. B. Harmon, J. Amer. Chem. SOC., 1961, 83, 865; G. A.64R. H. Wentorf, J. Chem. Phys., 1961, 34, 809.65 J. Goubeau and W. Anselment, 2. anorg. Chem., 1961, 310, 248.6aR. E. Davis and J. A. Gottbrath, Chern. and Ind., 1961, 1961. .67A. Hansson, Acta Chem. Scand., 1961, 15, 934.'j8H. Clasen, Angew. Chem., 1961, 73, 322.1166.83, 1766.1961, 18, 108.220.Olbh and W. S. Tolgyesi, J. Org. Chem., 1961, 26, 231986 INORGANIC CHEMISTRYwith bromine or iodine and with hydrogen iodide according to the equa-tions 692LiAlH, + 4X2 + LiA12X, + LiX + 4H2BLiAlH, + 8HI + LiAl,I, + LiH + SH,.Indications of the existence in benzene solution of 2 : 1 complexes of tertiaryamines and aluminium hydride have been obtainede70 The latter com-pound reacts with isopropyl borate according to the equation4A1H3 + 3B(OR), -+ A1H3,3BH,,3Al(OR),.The product is a reducing agent comparable in power to aluminium boro-hydride (of which it may well be the aluminium isopropoxide adduct) andcan be used in a wide range of organic solvents.71It has been pointed out that the Raman spectra of Al,Me,Cl, andAI,Me,Cl,, which have been written with methyl bridges, are also compatiblewith the formulations Me,Al+ AlC1,- and Me2Al+ Me,AlC12- ; the equivalenceof all the methyl groups in these compounds, which is apparent in the nuclearmagnetic resonance spectra, could then arise by chlorine exchange.72Amines react with alkylaluminiums or alkylaluminium chlorides, giving1 : 1 adducts; when these are pyrolysed, intermolecuIar condensation occurswith the formation of alkanes and A1-N bridged polymers.73 Organomercuryand organolithium compounds have been used to prepare alkyl and vinylderivatives from lithium aluminium hydride [e.g., LiAl( CH=CH,),], amineadducts of aluminium hydride (e.g., Bu,Al,NMe,), and several other com-p0unds.7~ Dialliylamino-derivatives of aluminium have been made by thereactions 75AlH,,NR, + 3HNR’, + Al(NR’,), $.3H2 + NR,andCryoscopy in benzene shows that most of them are associated in this solvent.Boron trichloride decomposes the compounds, e.g.,2BCl, + (Me,N),Al-+ 2Me,N*BCl2 + Me,N*AlCl,.The cyclopentadienyl compound (C,H,)AlEt, has been prepared fromdiethylaluminium chloride and cyclopentadienylpotassium ; it reacts withtitanium(m) chloride to form (C,H,),TiCl,*AlEf,.76The compounds MRAlCl,, where M = Li, Nay or K and R = Me or Et,have been obtained by heating alkali-metal chlorides and alkylaluminium&chlorides; they are solids stable up to 300°, but they react with atmo-spheric oxygen, alcohols, or ethers. 77Al(NR’,), + AlCl, -+ Al(KR’,),Cl + Al(NR’,)Cl,.69F. Klanberg and H. W. Kohlschiitter, Ber., 1961, 94, 781.70R. K. Ruff and M. F. Hawthorne, J . Amer. Chem. SOC., 1961, 83, 535.71 J. Kollonitsch, Nature, 1961, 189, 1005.V2R. E. Glick and A. Zwickel, J . Inorg. Nuclear Chem., 1961, 16, 149.7 3 A. W. Laubengayer, J. D. Smith, and G. G. Ehrlich, J . Amer. Chem. SOC., 1961,83, 542.74 J. K. Ruff, J . Amer. Chem. SOC., 1961, 83, 1798; F.M. Peters and B. Bartocha,Chem. and I n d . , 1961, 1271; B. Bartocha, A. J. Bilbo, D. E. Bublitz, and M. Y. Gray,2. Naturforsch., 1961, 16b, 357; B. Bartocha and A. J. Bilbo, J . Amer. Chem. SOC.,1961, 83, 2202.76 J. K. Ruff, J . Amer. Chem. SOC., 1961, 83, 2835.7sU. Giannini and S. Cesca, Gazzetta, 1961, 91, 597.77G. J. Sleddon, Chem. and I d . , 1961, 1492SHARPE: TYPICAL ELEMENTS 8'7An X-ray study of the complex Al2Br6,C6H6 suggests that the com-ponents are held together only by van der Waals bonding, though the pos-sibility of charge-transfer interaction between the n-electrons of the ringand the bridge bromine atoms of the inorganic moiety cannot be entirelyexcluded. 78Gallium, indium, and thallium. When gallium dissolves in 1 hf-per-chloric acid, Ga+ appears to be formed as an intermediate species.79Trivinylgallium, a liquid which is hydrolysed by water or acid and whichpolymerises above 70", is obtained by the action of divinylmercury on galliumat room temperature.Group IV.--Carbon.The reduction of mercuric salts in aqueous solutionby carbon monoxide appears to proceed by the mechanism(fast)(fast)-Hg2+OH2 + CO + [-Hg-CO,H]+ + H+ (Slow)[-Hg-CO,H]+ -+ Hg + CO, + H+Hg + Hg2+ -+ HgZ2+Carbon monoxide also reduces permanganate, and the reaction is stronglycatalysed by Ag+ or Hg2+ (but not by Cu2+, Fe3+, Cd2+, or T13+); forcatalysis by mercuric ion, intermediates such as [-HgCO,MnO,] aresuggested.81The C0,- ion has been shown from a study of its electron spin resonancespectrum to be bent, the LOCO being about 134".s2 The compound oftriethylphosphine and carbon disulphide is a zwitterion Et,P +-CSS -.83When finely divided sodium hydrogen carbonate dispersed in ether is cooledto -30" and treated with hydrogen chloride in ether, no evolution of gastakes place, and by cooling to -78" snow-white crystals of H,CO,,Et,Ocan be isolated.The solution is stable at -30" but the crystals decomposerapidly a t - 10". The dietherate of thiocarbonic acid, an orange-colouredoil, is similarly obtained by decomposing a solution of barium thiocarbonatein ether with gaseous hydrogen chloride.88Reviews have been given of silanes and their derivative^,^^the synthesis and reactions of organo-silicon, -germanium, and -tin com-pounds, 86 and compounds containing Si-N bonds.87Active silicon is obtained by the action of one mol.of chlorine on calciumdisilicide suspended in carbon tetrachloride a t 2 0 4 0 " ; by the furtheraction of another mol. of chlorine the red subchloride Sic1 is produced.Both compounds react violently with water or methanol.88 Silylpotas-sium, KSiH,, is prepared from silane and potassium in 1,2-dimethoxyefhaneSilicon.D. Eley, J. H. Taylor, and S. C. Wallwork, J., 1961, 3867.79K. Schug and A. Sadowski, J. Arner. Chem. SOC., 1961, 83, 3538.J. P. Oliver and L. G. Stevem, J . Inorg. Nuclear Chem., 1961, 19, 378.slA. C. Harkness and J. Halpern, J . Amer. Chem. SOC., 1961, 83, 1258.82D. W. Ovenall and D. H. Whiffen, Mol. Phys., 1961, 4, 135.a3 T.N. Margulis and D. H. Templeton, J . Amer. Chem. SOC., 1961, 83, 995.84 A. G. Galinos and A. A. Carotti, J . Amer. Chem. SOC., 1961,83,752; A. G. Galinos85A. G. MacDiarmid, Adv. Inorg. Chem. and Radiochem., 1961, 3, 207.8sA. D. Petrov and V. F. Mironov, Angew. Chern., 1961, 73, 59.R. Fessenden and J. S. Fessenden, Chem. Rev., 1961, 61, 361.8 e E . Bonitz, Ber, 1961, 94, 220.Bull. SOC. chirn. France, 1961, 141588 IN 0 RG ANIC C H E Ril: I S T R Yor from potassium and disilane; it reacts with water, hydrogen chloride,diborane, and methyl chloride. No disilane is formed in its reaction withsilyl bromide. If the expected adduct K+H,B*SiH,- is formed in thereaction with diborane, it disproportionates, and potassium borohydride isproduced.89 The preparation of silyl and arylsilyl halides by reactionssuch asPhSiH, + HX -3 PhH + SiH,XPhSiH,X + HX + PhH + SiH,X,(X = Br or I)(X = C1 or Br)(X = Br or I)has now been described in detail.g0 Mixed halides, e.g.SiH,BrI, dispro-portionate readily.Catenated silicon compounds which have recently been prepared includeC1SiPh,*SiPh2*SiPh2*SiPh2Cl (from cyclic Si,Ph8 and mercuric chloride), andMe,Si*SiMe,*SiMe,*SiMe, (from sodium-potassium alloy and Me,Si*SiMe,Cl). 91The pyrolysis of tetramethylsilane results in the formation of thecompound Me,Si:CH*SiMe,, the first well-defined compound reported tocontain a silicon-carbon double bond. Bromine is added, formingMe,SiBr*CHBr*SiMe, ; hydrogen bromide reacts to form Me,SiBr*CH,SiMe,.92Disiloxane does not form stable adducts with boron trifluoride; even at-78" cleavage of the Si-0 bond occurs:Ph,SiH, + HX+ PhH + PhSiH,S(SiH,),O + BF, + SiH,F + SiH,*OBF,.Siloxyboron dichloride is stable at room temperature, but the difluoride dis-proportionates into silyl fluoride, boron trifluoride, and boron trioxide.Disilthian does not react with boron trifluoride at all, sulphur attached totwo silicon atoms showing, as in other compounds, no electron-donatingproper ties.The liquid dimethylsiloxane heptamer has been shown to be very stabletowards attack by active nitrogen, but a slow reaction leading to the pro-duction of hydrogen cyanide and ammonia has been dete~ted.9~ Whensilane reacts with methanol at room temperature, a mixture of methoxy-silanes results, but the monosubstituted silane is not among them.Thiscompound can, however, be made from methanol and the trimethylamineadduct of silyl iodide; towards diborane it is found to be, as would be ex-pected, a weaker Lewis base than dimethyl ether.95 The compounds(Me,SiSe),, (Me,SiSe),, (Me,GeSe),, and (Me,SnSe), have been obtained bythe general reactionMe2MCl, + Na,Se + Me,MSe + 2NaClin dry benzene ; trimethylchlorosilane reacts similarly to give hexamethyl-disilyl selenide, and triphenylchlorostannane gives the analogous tin com-8sM. A. Ring and D. M. Ritter, J . Amer. Chem. SOC., 1961, 83, 802.G. Fritz and D. Kummer, Ber., 19b1, 94, 1143; 2. anorg. Chem., 1961, 310, 327.slH. Gilman and A. W. P. Jarvie, Chem.and In&., 1960, 965; G. R. Wilson andOZG. Fritz and J. Grobe, 2. anorg. Chem., 1961, 311, 325.ssM. Onyszchuk, Canad. J . Chem., 1961, 39, 808.J. L. Weininger, J . Amer. Chem. SOC., 1961, 83, 3388.OsB. Sternbach and A. G. MacDiarmid, J . Amer. Chem. SOC., 1961, 83, 3384.A. G. Smith, J . Org. Chem., 1961, 26, 557SHARPE: TYPICAL ELEMENTS 89Salts containing the triphenylsilyltriphenylborate anion or its pound.96germanium analogue are obtained by the reactionPh,MLi + Ph,B +- Li(Ph,M*BPh,).Both anions are very readily hydrolysed, but they are stable enough inmethanolic solution for precipitations with large inorganic and organiccations to be carriedTrends in the strengths of the compounds Ph,M*OH as hydrogen-bonddonors and acceptors suggest that dative n-bonding from oxygen to M isstrong when M is silicon, weaker when M is germanium, and negligible whenM is carbon, tin, or lead.98Trimethylgermanyl trimethylsilyl sulphate is obtained by the reactions(Me,GeO),SO, + ZLiO*SiMe, --+ Li,SO, + 2Me,Ge*O*SiMe,The chromate, selenate, and arsenate can be prepared similarly.The sd-phate disproportionates when it is heated; the chromate explodes.99 Themixed oxide, which has also been made by the reaction Me,GeCl +LiO-SiMe, --j. LiCl + Me,Ge*O*SiMe,, is cleaved by aluminium chlorideaccording to the equation looMe,Ge.O-SiMe, + AlCl, -+ Me,GeCl + Me,Si*O*AlCl,.Trimethylsilyl esters of the type R*CO,SiMe, react with trimethylsilyl-amines to form hexamethyldisiloxane and an organic amide, and the reac-tion is catalysed by acids.101Dimethylaminobromosilanes are obtained by the action of dimethyl-amine on silicon tetrabromide ; the corresponding fluorosilanes may be madefrom dimethylainine and chloro- or bromo-fluorosilanes, the latter com-pounds being obtained by cleavage of dimethylaminohalogenosilanes withboron trifluoride.lo2Silyl-substituted alkali-metal amides can be made from bistrialkylsilyl-amines and phenyl-lithium, sodamide, or metallic potassium; they aresoluble in nonpolar organic solvents, form adducts with ethers and withpyridine, and readily react with chlorosilanes, e.g.(Me,Si),NLi + ClSiMe, + (Me,Si),N.SiMe, + LiClThe tris-silylamines so obtained are waxy solids of low melting point whichcan be distilled in vucuo without decomposition and are resistant to hydro-lysis.lo3 Several silyl-substituted hydrazines have been made by thereactionsR,Si*NH*NH.SiR, + LiPh + R’,SiCl + (R’,Si)(R,Si)NNH*SiR, + LiCl + PhHPh,SiCl, + 4RR’N.NH2 +- B(RR’N*NH,)Cl + RR’N*NH*SiPh,-NH*NRR’.Me,Ge*O*SiMe, + SO, -+ Me,Ge*O*SO,*O*SiMe,.__ - _ _ ~ _______~~BsM.Schmidt and H. Ruf, Angew. Chem., 1961, 73, 64.O7 D. Seyferth, G. Raab, and S. 0. Grim, J . Org. Chem., 1961, 26, 3034.seR. West, R. H. Baney, and D. L. Powell, J . Amer. Chem. SOC., 1960, 82, 6269.OBH. Schmidbaur and M. Schmidt, Ber., 1961, 94, 2137, 2451.looH. Schmidbaur and M. Schmidt, Ber., 1961, 94, 1138, 1349.lolR. M. Pike, Rec. Trav. chim., 1961, 80, 819.loaG. Schott and G. Gastmeier, 2. Chem., 1961, 1, 123; H.Grosse-Ruyken andlo3U. Wannagat and H. Niederpriim, Ber., 1961, 94, 1540; Z. anorg. Chem., 1961,R. Kleeaaat, 2. anorg. Chem., 1961, 308, 123.308, 33790 INORGANIC CHEMISTRYIn the latter case R = R' = Me or R = H, R' = Ph, and the products arevery sensitive to decomposition by water and readily undergo condensationinto cyclic compounds.104 Trimethylchlorosilane reacts with urea at 300"to form trimet hylsil yl is0 cyanat e .I05Many examples of the cleavage of silicon-nitrogen bonds by boron, alu-minium, or phosphorus trihalides have been reported, e.g.106(Me,Si),NH + BF, --+ Me,SiF + Me,Si-NH*BF,Me,Si*NMe, + BC1, -+ Me,SiCl + Me,N*BCl,.The imide Si,(NH), is the only silicon-containing product of the decom-position of disilicon hexachloride by ammonia; it is hydrolysed by waterto ammonia, hydrogen, and silica, and undergoes a complex thermaldecomposition into ammonia and a mononitride.lo7 Disilylcyanamide,(SiH,),N.CN, which has been made by the action of silyl iodide on silvercyanamide, forms an unstable adduct with boron trifluoride, and is decom-posed into diaminomethylene &chloride andmonochlorosilane by hydrogen chloride.108 The I I first four-membered cyclic silicon - nitrogenMe3Si'N-SiMe2 (2) systeni (2) has been obtained by the actionof dimethyldichlorosilane on the dilithiumderivative of the amine Me3Si*NH*SiiMe,*NH-SiMe3.109Silicon tetrafluoride reacts with silicon disulphide at 1000" to form thecompound F,Si*S,*SiF,, which on cooling slowly reverts to the startingmaterials.l o Silicon, tin, or boron halides usually form addition compoundswith sulphoxides, but occasionally a chloro-substituted sulphide results,e.g.lll2Me,SO + SiCI, -+ 2MeS.CH2C1 + SiO, + 2HC1.The preparation of the chloride Si5Cll, by the action of trimethylamine ondisilicon hexachloride has been described in detail, and it is suggested thatthe compound may have the neopentyl structure. 112 Cyclic chlorosil-oxanes [SiOCl,], with n = 3, 4, or 5, and lower open-chain compoundsSi,O,,-,,CI,,,+,, are obtained from the interaction of oxygen and silicontetrachloride at 1000 O . 1 1 3 Silicon tetrachloride in ether reacts with silvernitrate in acetonitrile at -40" to yield silver chloride and a solution-fromwhich pyridine precipitates the compound Si(N03)4,2py.114Further work on the mechanism of substitution in silicon compoundshas been reported, and it has been shown that substitution at an asymmetricsilicon atom may be accompanied by inversion or retention of codigura-104U.Wannagat and H. Niederpriim, 2. anorg. Chem., 1961, 310, 32; 1961, 311,105 J. Goubeau and D. Paulin, Ber., 1960, 93, 1111.106 M. Becke-Goehring and H. Krill, Ber., 1961,94, 1059; H. Noth, 2. Naturfwsch.,107 M. Billy, Bull. SOC. chim. Prance, 1961, 1550.lo*E. A. V. Ebsworth and M. J. Mays, J., 1961, 4879.lo9 W. Fink, Angew. Chem., 1961, 73, 736.1lOV. Gutmann, P. Heilmayer, and K. Utvary, Monatsh., 1961, 92, 942.111M. F. Lappert and J. K. Smith, J., 1961, 3224.112 A. Kaczmarczyk, M. Millard, and G.Urry, J . Inorg. Nuclear Chem., 1961,17, 188.1laD. W. S. Chambers and C. J. Wilkins, J., 1960, 5088.l141. R. Beattie and G. J. Leigh, J., 1961, 4249.Me2S i - N.S i Me.3270.1961, 16b, 618SHARPE: TYPICAL ELEMENTS 91tion.l15 Evidence has also been presented which suggests that the reactionMe,SiCH,*CH,*Cl + RON + Me,Si*OR + C,H, + HCl(where R = H or Et) takes place by a limiting siliconium-ion mechanism.116Yields of germane and stannane in the boro-hydride reduction of germanium and tin compounds can be improved some-what by dropping an alkaline solution of sodium borohydride and germaniteor stannite into dilute acid; however, it should be noted that no silane isobtained by a similar reaction with sodium ~i1icate.l~' Passage of mono-germane a t 0.5 atm.and -78" through a silent electric discharge resultsin the formation of hydrides containing up to eight atoms of germanium.l18Germanium difluoride, a white solid melting at 110", is obtained byreduction of the tetrafluoride with the element. It is immediately hydro-lysed by water, and is converted by selenium tetrafluoride into the com-pound GeF4,2SeF,.119 Monofluorogermane has been made by the action ofargentous fluoride on the bromo-compound; it forms a 1 : 2 adduct withammonia, but the product is unstable at 25" and is converted into ammoniaand a 1 : 1 adduct for which the structure GeH,*NH,+ F- is suggested.Monofluorogermane readily disproportionates into the difluoro-compoundand germane.120 Hexachlorogermanates are formed only by rubidium,czsium, and large organic cations ;121 several complexes of germanium tetra-chloride and heterocyclic bases have been described.122Trimethylchlorogermane can be obtained by the action of methyl-lithium or methylmagnesium iodide on the dimethyldichloro-compound,123or by the interaction of tetramethylgermane, hydrogen chloride, and alu-minium ~hloride.12~ It reacts with silver carbonate to form silver chloride,carbon dioxide, and hexamethyldigermoxane, (Me,Ge),O, which does notform a stable complex with boron trifluoride but undergoes cleavage accord-ing to the equationGermanium, tin, und lead.3(Me,Ge),O + ZBF, -+ 6Me,GeF 4 B,O,.Attempts to make digermoxane, (GeH,),O, have been unsuccessful. Meth-oxytrimethylgermane, which is made by the reactionMe,GeBr + NaOMe + Me,GeOMe + NaBr,does, however, form a stable 1 : 1 adduct with boron trifluoride; evidentlyd, - p , bonding, if it occurs here, does not appreciably alter the donorpr0perties.12~ Trimethylchlorogermane reacts with silver vanadate, chrom-ate, selenate, or perrhenate to form esters; the same compounds can alsol15L.H. Sornmer, C. L. Frye, M. C. Musolf, G. A. Parker, P. G. Rodewald, K. Wll6L. H. Sommer and G. A. Baughtman, J . Amer. Chem. SOC., 1961, 83, 3346.11' W. L. Jolly, J . Amer. Chern. Soc., 1961, 83, 335.11* J. E. Drake and W. L. Jolly, Proc. Chem. SOC., 1961, 379.lloN. Bartlett and K. C. Yu, Canad. J . Chem., 1961, 39, 80.laoT. N. Srivastava and M. Onyszchuk, Proc. Chem. Soc., 1961, 205.lalV.V. Udovenko and Y. A. Fialkov, Zhur. nemg. Khim., 1960, 5, 1502 [728].laaV. G. Lebedev and V. G. Tronev, Zhur. newg. Khim., 1960, 5, 1725 [837].1aJM. Schmidt and I. Ruidisch, 2. anorg. Chem., 1961, 311, 331.114 J. E. GriEths and M. Onyszchuk, Canad. J . Chem., 1961, 39, 339.Michael, Y. Okaya, and R. Pepinsky, J . Amer. Chem. Soc., 1961, 83, 221292 INORGANIC CHEMISTRYbe made by the action of the appropriate oxide on hexamethyldi-germoxane.Dichlorogermanium phthalocyanine has been made from the tetra-chloride and phthalocyanine in quinoline a t 240°, and by replacement of thechlorine atoms the dihydroxy-compound has been prepared.126The Raman and infrared spectra of the trimethyltin halides show thatonly the fluoride has an ionic lattice; there is a planar distribution of valen-cies round the tin in the Me3Sn+ cation.The other halides are associatedby means of halogen bridging.12' The sodium salt NaSnMe, reacts withtrimethylborane-ammonia in liquid ammonia, forming hexamethyldi-stannane. This compound is catalytically decomposed by boron tduoridein ether, giving methyltin polymers and tetramethyltin; the latter compoundthen reacts with the boron trifluoride, forming methylboron difiuoride andtrimethyltin tetrafluoroborate. The decomposition of hexamethyldistan-nane, like that of trimethylstannane, is also catalysed by diborane.128When triphenyltin chloride reacts with magnesium in tetrahydrofuran, ethylbromide being added as an initiator, the compound (Ph,Sn),Mg is formed(hexaphenyldistannane is an intermediate) ; .ammonium chloride solutionhydrolyses the compound to triphenylstannane and magnesium hydrox-ide.129 Tri-n-butylstannyl-lithium reacts with trimethylchlorosilane andwith carbon dioxide as if it contained butyl-lithium in equilibrium withdibutyltin.Triphenylstannylsodium, which can be made from sodiumnaphthenide and tetraphenyltin or triphenyltin bromide, reacts normallywith ethyl bromide but as a reducing agent with benzophenone, oxygen,carbon dioxide, and sulphur dioxide. The interaction of trimethyl-stannylsodium and chloroform gives not Me,Sn*CH:CHBnMe,, as reportedearlier, but Me3Sn.CH2*SnMe3. l 3 l The preparation of some new modifica-tions, and several new reactions, of diphenyltin have been r e p ~ r t e d , l ~ ~ andit has been shown that di-n-butylchlorostannane can be made by interactionof the dihydride and the dichloro-compound at room temperature.133Several compounds containing Sn-0-Si linkages have been obtained bythe co-hydrolysis of a dialkyltin dichloride and trimethylchlorosilane or byreactions of the typeMe&-OLi + Me3SnC1 + LiCl + Me,Si*O.SnMe,.The second method can be modified for use in the preparation of Pb-O-Sicompounds ; both the tin and the lead compound show considerable thermalstability, but the vapour of the lead compound explodes with oxygen attemperatures above 150°.134125M.Schmidt, H. Schmidbaur, I. Ruidisch, and P. Bornmann, Angew. Chem.,1961, 73, 408; M. Schmidt, I. Ruidisch, and H. Schmidbaur, Ber., 1961, 94, 2451.126 R.D. Joyner and M. E. Kenney, J . Amer. Chem. SOC., 1960, 82, 5790.1 2 7 H . Kriegsmann and S. Pischtschan, 2. anorg. Chem., 1961, 308, 212.128 A. B. Burg and J. R. Spielman, J . Amer. Chem. SOC., 1961, 83, 2667.129 C. Tamborski and E. J. Soloski, J . Amer. Chem. SOC., 1961, 83, 3734.130D. Blake, G. E. Coates, and J. M. Tate, J., 1961, 618.131 H. D. Kaesz, J . Amer. Chem. Soc., 1961, 83, 1514.1*2H. G. Kuivila, A. K. Sawyer, and A. G. Armour, J . Org. Chern., 1961, 26, 1426;133 A. K. Sawyer and H. G. Kuivila, Chem. and Ind., 1961, 260.134 R. Okawara, D. G. White, K. Fujitani, and H. Sato, J . Amer. Chem. SOC., 1961,H. G. Kuivila and E. R. Jakusik, ibid., p. 1430.83, 1342; H. Schmidbaur and M. Schmidt, ibid., p.2963SHARPE: TYPICAL ELEMENTS 93The nuclear magnetic resonance spectra of mixtures of stannic chloride,bromide, and iodide show that all possible mixed halides are pre~ent.1~5The infrared spectra of the 2 : 1 complexes of esters and stannic chlorideshow the acyl-oxygen atom to be the donor.136Further work on perfluoroalkyl and perfluorovinyl derivatives has beendescribed ;I37 the ease of cleavage of organic groups from tin by protonic acidsis perfluorovinyl M phenyl > vinyl > alkyl > perfluoroalkyl. Organotinhalides can be perfluorovinylated by addition of bromotrifluoroethylene andthe organotin compound in tetrahydrofuran to magnesium turnings a t-10"; cleavage of the perfluorovinyl group from the products can beeEected by alcohol, acetic acid, hydrogen bromide, iodine, or sodium eth-The oxychloride, SnOCl,, can be made by the interaction of stannicchloride and, chlorine monoxide; it is a very hygroscopic solid which formsaddition compounds with phosphorus oxychloride and with pyridine.139 AnX-ray examination of the complex K,SnC1,,H20 shows that it contains C1-and pyramidal SnC1,- i0ns.1~0 The compounds formerly reported as tetra-alkyldihalogenodistannanes and made by the action of amines on dialkyltindihalides are, in fact, complexes of dialkyltin dihalides and dialkyltinoxides.141 It has been shown that the composition of " stannous hydroxide "is best represented by the formula Sn50,(OH)4; it is dehydrated in onestage at temperatures above 120" to give an orange modification ofstannous 0xide.142 Of the various basic stannous nitrates reported, onlySn3(OH)4(N03)2 can be obtained in a pure state from aqueous solutions, andit is interesting to note that this substance is a high exp10sive.l~~ A basicstannous phosphate Sn,(PO,),(OH),,H,O has been shown to be formed inthe reaction between some stannous salts and hydro~yapatite.1~4Di- and tri-alkylplumbanes can be made by reduction of the correspond-ing chlorides with potassium borohydride in liquid ammonia or lithium alu-minium hydride in dimethyl ether. Trimethylplumbane adds ethylene toform ethyltrimethylplumbane, and ammonia to form the green compoundNH4PbMe,, which decomposes via the red salt NH4Pb,Me5 into lead, tetra-methylplumbane, methane, and hydrogen, and reacts with trimethylchloro-plumbane in liquid ammonia to give he~amethyldiplumbane.~~~ The infra-red spectra of trimethyl-lead carboxylates suggest that these compoundscontain Me3Pb+ ions, with a planar configuration round the lead.146135 J.J. Burke and P. C. Lauterbur, J . Amer. Chem. SOC., 1961, 83, 326.1361\1. F. Lappert, J., 1961, 817.13' H. D. Kaesz, J. R. Phillips, and F. G. A. Stone, J . Amer. Chenz. SOC., 1960, 82,6228; H. D. Kaesz, S. L. Stafford, and F. G. A. Stone, ibid., p. 6232; R. D. Chambers,H. C. Clark, and C. J. Wilkins, Canad. J . Chem., 1961, 39, 131.lSsD. Seyferth, G. Raab, and K. A. Brlindle, J . Org. Chem., 1961, 26, 2934.13@K. Dehnicke, 2. anorg. Chem., 1961, 308, 72.laOD. Grdenic and B. Kamenar, Proc. Chem.SOC., 1961, 304.141 D. L. Alleston and A. G. Davies, Chem. and I d . , 1961, 949.142 J. D. Donaldson and W. Moser, J., 1961, 835; J. D. Donaldson, W. Moser, and143 J. D. Donaldson and W. Moser, J., 1961, 1996.R. Collins, W. Nebergall, and H. Langer, J . Amer. Chem. Soc., 1961, 83, 3725.146 W. E. Becker and S. E. Cook, J . Amer. Chem. SOC., 1960, 83, 6264; R. Duffy14"R. Okawara and H. Sato, J . Inorg. Nuclear Chem., 1961, 16, 204.W. B. Simpson, J., 1961, 839.and A. K. Holliday, J., 1961, 167994 INORGANIC CHEMISTRYTriphenyl-lead azide has been made by the action of hydrazoic acid onthe hydroxide in ethanol-chloroform, and shows no explosive pr0perties.1~7Lead chloride or bromide reacts rapidly with phenyl-lithium or phenyl- ormesityl-magnesium bromide in tetrahydrofuran at -40 O ; the deeplycoloured solutions which result involve the equilibria 148PbAr, + ArLi + Ar,PbLior PbAr, + ArMgBr + Ar,PbJIgBr.Group V.-Nitrogen. When ammonium fluoride is subjected to 3800 atm.pressure at room temperature? a cubic form is produced with a diminutionin volume of about 28%; no work on the structure of this phase has yet beenreported, but the result strongly suggests the formation of a sodium orcssium chloride form.149 A study of the NH,HF,-HF system has con-firmed earlier reports of the existence of NH,H,F4 and NH4H,F,, but notNitrogen trifluoride reacts with trifluoroacetonitrile when the two arepassed over czesium fluoride at 520°, forming the compounds CF,NF,,(CF,),NF, CF,*NCF,, and ( CNF),.With perfluoropropene over the samecatalyst at 320", very little C3F8 is formed, and the major products are(CF,),CF*CF(CF,),, (CF,),CF*NF,, and (CF3),C:NF.151 More work on thefluoride N,F4 has been described, and it has been shown to exist in equi-librium with NF,* radicals? these being responsible for the colour of theordinary p r 0 d ~ c t . l ~ ~ Under the influence of ultraviolet light it convertschlorine into chlorodifluoramine, ClNF,, hexaphenylethane into Ph,C*NF2,a-diketones into NN-difluoro-amides, and alkyl iodides into NN-difluoro-alk~1amines.l~~ The interesting debate on the structure of the higher-boiling isomer of N2F2 has been continued; all that can be said is that a firmdecision between cis-FNNF and F2N=N is not yet possible.154 The proper-ties of the thiofluorides NSF and NSF, have now been described in detail, andthe preparation of monomeric NSCl by the action of chlorine on the mono-fluoro-compound has been r e ~ 0 r t e d .l ~ ~The yellow solid formed by addition of excess of sodium nitrite to a solu-tion of sodium in liquid ammonia is mainly Na,N,O,, but its electron-spinresonance spectrum confirms that Na,NO, is a minor ~0nstituent.l~~ Nitricacid is extracted from 6--16~-aqueous solution into benzene or toluene asthe hemihydrate, for which a structure intermediate between (3) and (4)is suggested.15' Salts and esters of the acid P(O)(OH),*NN*P(O)(OH), haveof147E. Lieber and F. M. Keane, Chem. and Ind., 1961, 747.14*F. Glockling, K. Horton, and D.Kingston, J . , 1961, 4405.lasR. Stevenson, J . Chem. Phys., 1961, 34, 346.150R. D. Euler and E. F. Westrum, J . Phys. Chem., 1961, 65, 1291.R. D. Dresdner, F. N. Tlumac, and J. A. Young, J . Amer. Chern. Soc., 1960, 82,152F. A. Johnston and C. B. Colburn, J . Amer. Chem SOC., 1961, 83, 3043.163 R. C. Petry and J. P. Freeman, J. Amer. Chem. SOC., 1961,83,3912; J. W. Frazer,16*R. Ettinger, F. A. Johnson, and C. B. Colburn, J . Chem. Phys., 1961, 34, 2187;1650. Glemser and H. Richert, 2. anorg. Chem., 1960, 307, 313, 328; 0. Glemser166 H. C. Clark, A. Horsfield, and M. C. R. Symons, J . , 1961, 7.157 C. J. Hardy, B. F. Greenfield, and D. Scargill, J., 1961, 90.6831.J. Inorg. Nuclear Chem., 1961, 16, 63.R. H. Sanborn, ibid., p. 2188.and H.Perl, NaturwisS., 1961, 48, 620SHARPE: TYPICAL ELEMENTS 95been obtained by oxidation of the corresponding derivatives of hydrazine,e.g. K,N,H,P,O,, with hydrogen peroxide, mercuric oxide, or N-bromosuc-cinimide; the potassium salt is decomposed by heat or by acids accordingto the equations 15*KZO,P.N:N.P03K, + N, + K4P20,2K203P.N:N*PO,Kz + 4KZO -+ N, + NzH, + 4KzHPO4.Di-imide, N2H2, previously postulated as an intermediate in certainoxidations of hydrazine, has been shown to possess a finite lifetime, and itsapplication to the reduction of organic compounds has been ~tudied.1~9The compound HCP has been obtained by passing phos-phine through a low-intensity rotating arc struck between graphite elec-trodes, and quenching the gaseous products at -196".It is a very reactivecolourless gas stable only at temperatures below its triple point (-1.24');it polymerises rapidly at -78" to a black solid, and combines with hydrogenchloride, yielding methyldichlorophosphine.160 Tetraphenylphosphoniurnborohydride has been made from the hydroxide (prepared by ion-exchange)and potassium borohydride ; its thermal decomposition gives benzene andPh3P*BH,.161 Attempts to make phosphine oxide, PH,O, by the action oflithium hydride or lithium aluminium hydride on phosphoryl chloride orbromide show that the compound is highly unstable, decomposing even at-115" to water and a polymeric monohydride of phosphorus.162 The rela-tive strengths of some alkylphosphines as bases towards trimethylboron havebeen compared, and the chemistry of methylenetriphenylphosphorane,Ph,P:CH,, has been studied extensively : l 6 3 the compound adds trimethyl-bromosilane to give [ Ph,P*CH,*SiMe,]Br and boron trifluoride to givePh,P +*CH,*BF3-. Tetramethyldiphosphine combines with ethylene below300", forming mostly Me,P*CH,*CH,*PMe,, which forms mono- and di-borane adducts ; tetramethyldiphosphine itself combines with diboraneforming H,B*PMe,*PMe,*BH,, which is converted by heat into (Me,P*BH,),,Phosphorus.15* H.Bock and G. Rudolph, Ber., 1961, 94, 1457.15# E. J. Corey, W. L. Mock, and D. J. Pasto, Tetrahedron Letters, 1961, No. 11,lsoT. E. Gier, J . Arner. Chem. SOC., 1961, 83, 1769.161€€. G. Heal, J . Inorg. Nuclear Chem., 1961, 16, 208.laa E. Wiberg and G. Miiller-Schiedmayer, 2.anorg. Chem., 1961, 308, 352.347; J . Amer. Chem. Xoc., 1961,83, 2957; E. E. van Tamelen, R. S. Dewey, M. F. Lease,and W. H. Pirkle, &bid., p. 4302.H. D. Krtesz and F. G. A. Stone, J . Amer. Chem. SOC., 1960, 82, 6213; D. Sey-ferth and S. 0. Grim, ibid., 1961, 83, 1610, 161396 INORGANIC CHEMISTRYwhere n = 3 or 4.16& The compounds P,(NMe2)4 and P,(NMe,), [i.e.,(Me,N) ,POP( NMe, ) *P(NMe, ) 2] are obtained when bisdimet hylaminochlor o -phosphine is treated with sodium, and many reactions of the former com-pound have been described. Bromine converts it into (Me,N),PBr, oxygenforms a diphosphine oxide, diborane yields (Me,N),( H,B)P*P( BH,) (NMe2)2,, and hydrogen chloride, which forms a salt at low temperature, cleavesthe P-P bond and gives dimethylammonium chloride and a mixture ofphosphorus chlorides.165The chemistry of the halides of phosphorus, arsenic, antimony, andbismuth has been reviewed. 166 Phosphorus tri- and penta-fluorides areboth obtained in high yield by the action of calcium fluoride on the corre-sponding chloride at 300--400". The trifluoride has negligible acceptorproperties, but itsreactions with alkali-metal fluorides (which lead to the for-mation of hexafluorophosphates and phosphorus) may involve tetrafluoro-phosphites of the type MPF, as intermediates. The pentafluoride, on theother hand, is a very good electron-acceptor, and forms complexes withamines, ethers, nitriles, and sulphoxides, and is a good catalyst for ionicpolymer is at ion^.^^^ Tetrasulphur tetranitride reacts with phosphorus tri-chloride to form compound NP,Cl, which as the solid and in nitrobenzeneappears to be PC14+ PNCl,-.lsg With silver cyanide and with methylaminethe trichloride gives the compounds P(CN), and P4(NMe)6, respectively;169the latter compound is probably an analogue of P406.The cyclic compounds(PCF,), and (PCF,), react easily and reversibly with trimethylphosphine ortrimethylamine to form Me,P*PCF, or Me,N*PCF, ; traces of trimethyl-phosphine thus catalyse the interconversion of tetramer and pentamer, buthigher (PCF,), polymers do not appear to be formed.170Much further work on the phosphorus oxychloride and related solventsystems has been reported 171 and interpreted in terms of chloride-ion trans-fer. Serious doubts on the validity of this interpretation have, however,been expressed, and it has recently been shown that anhydrous ferric chloridein triethyl phosphate forms a solution very similar t o that in phosphorusoxychloride, the equilibriaFeCl, + Y3P0 + [FeCl,OPY,] + [FeCl(y-,)(OPk',)(l+~)]~+ + xFeC1,-+ [Fe(OPY3),I3+ +- 3FeC1,-,where Y = C1 or OEt, describing both systems.This mechanism is con-164 A. B. Burg, J . Anzer. Chem. SOC., 1961, 83, 2226.16sH. Noth and H.-J. Vetter, Ber., 1961, 94, 1505.166D. S. Payne, Quart. Rev., 1961, 15, 173.167E. L. Muetterties, T. A. Bither, M. W. Farlow, and D. D. Coffman, J . Irwrg.Nuclear Chem., 1961, 16, 52.168 0. Glemser and E. Wyszomirski, Nuturwiss., 1961, 48, 25.169 J.Goubeau, H. Haeberle, and H. Ulmer, 2. anorg. Chem., 1961, 311, 110;R. R. Holmes, J . Amer. Chem. Soc., 1961, 83, 1334.170A. B. Burg and W. Mahler, J . Amer. Chem. SOC., 1961, 83, 2388.171M. Baaz, V. Gutmann, and L. Hubner, Monatsh., 1961, 92, 135, 272, 707; M.Baaz, V. Gutmann, M. Y. A. Talaat, and T. S. West, ibid., pp. 150,164,714; M. Baaz,V. Gutmann, and J. R. Masaguer, ibid., pp. 582, 590; V. Gutmann and F. Mairinger,{bid., p. 720; M. Baaz, V. Gutmann, and L. Hubner, J . Inorg. Nuclear Chem., 1961,18, 276.17aD. W. Meek and R. S. Drago, J . dmer. Chem. SOC., 1961, 83, 4322SHARPE: TYPICAL ELEMENTS 97sistent with X-ray, Raman, and infrared spectral work, and the status ofthe phosphorus oxychloride, and indeed other oxyhalide, solvent systems hasclearly been severely challenged.A rapid preparation of sodium hypophosphate decahydrate from redphosphorus and bleaching powder has been described, and evidence has beenpresented to show that the crude oxidation product contains the calciumsalt of a new acid H,P407; a study of vibrational spectra shows the P,O,4-and S,0G2- ions to be isostru~tural.~~~ The esters CF,*P(OMe), andCF,*PO,C,H, have been made from trifluoromethyldichlorophosphine andmethanol and ethylene glycol, respectively, higher polymers also beingformed in the latter reaction.Neither ester shows any tendency to re-arrange, but the free acid (obtained by the action of hydrogen bromide onthe ester) exists almost entirely as the dimer of CF,*PH(0)*OH.174Another review of the chemistry of the phosphonitrilic halide polymershas been p~blished.1~~ The conversion of the chlorides into fluorides bythe action of argentous fluoride, sodium fluoride, and potassium fluoro-sulphinate, KSO,F, hqs been further de~cribed;l'~ it has been shown thatwhen the last reagent is used a PFCl group is more susceptible to halogenexchange than a PCl, group.Further work has also been reported on thealcoholysis 177 and aminolysis 178 of the chlorides. Some alkoxy-compoundsrearrange to give N-alkyl derivatives when they are heated at 200°, e.g.(5)-+(6) 179The synthesis of some tris-alkyl and -aryl derivatives of the trimer has beendescribed : (PhClPN), from the products of the interaction of phenyltetra-chlorophosphorane and ammonium chlorideY1*0 and (MeClPN), by the reac-tion sequence 181MeMgBr HClN,P,Cl,(NMe,), I___+ N,P,Me,(NMe,), d N,P,Me,Cl, + Me,NH.The shape of the eight-membered P-N ring in the tetramers is now seen to173 W.G. Palmer, J . , 1961, 1079, 1552.17*A. B. Burg and J. E. Griffiths, J . Arner. Chenz. SOC., 1961, 83, 4333.1 7 5 1 . A. Gribova and U. Ban-yuan, Uspekhi Khim., 1961, 30, 3 [l].1'6 R. Ratz and C. Grundmann, J . Inorg. Nuclear Chem., 1961, 16, 60; T. Moeller,K. John, and F. Tsang, Chem. and Ind., 1961, 347; A. C. Chapman, D. H. Paine, H. T.Searle, D. R. Smith, and R. F. M. White, J . , 1961, 1768.177B. W. Fitzsimmons and R. A. Shaw, Chem. and Ind., 1961, 109.178 S. I<. Ray and R. A. Shaw, J., 1961, 872; K. John, T. Moeller, and L.F. Audrieth,J . Amer. Chem. SOC., 1961, 83, 2608; S. G. Kokalis, K. John, T. Moeller, and L. F.Audrieth, J . Inorg. Nuclear Chem., 1961, 19, 191.I;leB. W. Fitzsimmons and R. A. Shaw, Proc. Chem. SOC., 1961, 258.leoF. S. Humiec and I. I. Bezman, J . Amer. Chem. SOC., 1961, 83, 2210.la1 G. Tesi and P. J. Slota, Proc. Chem. SOC. 1960 404.98 INORGANIC CHEMISTRYdepend on the nature of the substituents, being planar in (PNF,), andpuckered in (PNCl,), and [PN(NMe,),],.182The compound Cl,P:N*P(O)Cl, is obtained by the interaction of phos-phorus trichloride and dinitrogen tetroxide or phosphoric amides and pbos-phorus pentachloride or hydroxylammonium salts and phosphorus tri- orpenta-chloride. From the thioamide PS(NH,), and the pentachloride thecompound Cl,P(N:PCl,), results.Both acid chlorides are extremely reac-tive. 183 When methylammonium chloride is heated with phosphorus penta-chloride in tetrachloroethane the compound (MeWPCl,), is formed ; infraredspectroscopy suggests that this contains a four-membered planar ring inwhich the nitrogen and phosphorus atoms are, severally, positively andnegatively charged. lS4Tetraphosphorus triselenide reacts with liquid ammonia to form(NH4),[P4Se,(NH,),], thermally degraded successively into (NH,),(P,Se3NH),(NH,)(P,Se,NH,), and P,Se,.ls5Arsenic, antimony, and bismuth. The arsonium ion has been identifiedby its infrared spectrum in the products of the interaction of arsine andhydrogen chloride, bromide, or iodide at low temperature. No similarevidence for the existence of the stibonium ion was found.186 Conducti-metric titration of a solution of sodium in liquid ammonia with arsine orstibine shows that the salts MHNa, and MH,Na are formed; phosphine givesonly PH,Na.Alkali-metal derivatives of diphenylarsine have beenobtained from the metals and diphenylarsine in dioxan; their reactions withiodine and trimethylchlorosilane give the compounds Ph,As-AsPh, andPh,As*SiMe,, respectively. Trimethylfluorosilane reacts similarly with thepotassium derivative of arsine, forming (Me,Si),AsH and (Me,Si),As ; similarcompounds containing trimethylsilyl or trimethylstannyl groups bonded tophosphorus are obtained by analogous inethods.188 Arsenobenzene hasbeen shown to contain As,Ph, units, the arsenic atoms forming a six-membered ring in the << chair '' form.189In mixtures of hydrogen fluoride and antimony pentafluoride the ionsH2F+ and sbF,- are f0rmed.1~0 Arsenic trichloride reacts with dimethyl-amine to form the compound As,(NMe), analogous to the phosphorusderivative described ab0ve.1~1 The compound SbC1,+SbF6-, an isomer ofthe fluorination catalyst SbF3Cl2, has been prepared by the action of chlorineon antimony trifluoride.192 Esters of arsenic acid, readily obtained bylS2 G.J. Bullen., Proc. Chem. Xoc., 1960,425; H. McD. McGeachin and F. R. Tromans,J., 1961, 4777.183 1LI. Becke-Goehring, T. Mann, and H. D. Euler, Ber., 1961, 94, 193; 31. Becke-Goehring, A. Debo, E. Fluck, and W. Goetze, ibid., p. 1383.184 A.C. Chapman, W. S. Holmes, N. L. Paddock, and H. T. Searle, J., 1961, 1825.185H. Behrens and G. Haschka, Ber., 1961, 94, 1191.186 A. Heinemann, Naturwiss., 1961, 17, 568.1 8 7 H. J. Emelbus and K. MacKay, J., 1961, 2676.188K. Issleib and A. Tzschach, Angew. Chem., 1961, 73, 26; A. B. Bruker, L. D.189 S. E. Rasmussen and J. Danielsen, A4cta C'heru. Scand., 1960, 14, 1862; K.19oH. H. Hyman, L. A. Quartermain, &l. Kilpatriek. and J. J. Katz., J. Phys.191 H. Noth and H. J. Vetter, Naturuiss., 1961, 16, 553.192L. Kolditz and W. von der Leith, 2. anory. G'heitL., 1961, 310, 236.Balashova, and L. Z. Soborovskii, Doklady ,41;ad. Nauk S.S.S.R., 1960, 135, 843.Hedberg, E. W. Hughes, and J. Waser, Acta Cryst., 1961, 14, 369.Chem., 1961. 65, 123SHARPE : TYPIC-4L ELEMENTS 99oxidation of alkyl arsenites with bromine, react with hydrogen fluoride orarsenic trifluoride to yield esters of monofluoroarsenic acid ; these combinewith a further molecule of alcohol to give esters of formula l?As(OH)(OR),which dissociate in polar solvents, ions such as [As(OH)(OR),] + and[As( OH)(0R),Fz] - being formed.193 The compounds Ph,AsX, andPh,AsX,, where X = Br or I, are also good conductors in polar solvents, andthe structures Ph,AsX +X - and Ph,AsX+X,- have been suggested.lg4Several monomers and polymers containing Si-0-As and Sn-O-As link-ages have been made by methods of which the following illustrations arerepre~entative.1~3Ph3SiC1 + Ag,AsO, -+ (Ph,SiO),AsO4NH, + 2Ph,Si(OH), + 2PhAs1, + 4NHJ + PhAs([O*SiPh,*O],)AsPhMe,SnCl, + 2AsPhO(OH), -+ 2HC1 + SnMe,(O*AsPhO*OH),.The reduction of alkylbismuth chlorides or bromides by lithium alu-minium hydride at - 110 O in dimethyl ether leads to the formation of alkyl-bismuth hydrides.These substances slowly disproportionate at tempera-tures above -50" into trimet,hylbismuth and the unstable bismuthane, BiH,(extrapolated b.p. 17 ').I96Group V1.-A new fluoride of oxygen, 04F2, is obtained by the actionof an electrical discharge on a mixture of oxygen and fluorine at 60-77 O K ;it is a red-brown solid decomposing even at 90-110" K into trioxygendifluoride and oxygen.197An induced isotopic exchange of oxygen between hydrogen peroxide andwater has been observed during the interaction of hydrogen peroxide andOC1-, 104-, Mn04-, Fez+, Fe3+, and Ce4+ ions, and is attributed to theformation of peroxy-complexes. The exchange is much faster in nitric acidsolution than in solutions of sulphuric or perchloric acid, and it is suggestedthat it proceeds by the formation of N,05 and pernitric acid.The HO,radical is certainly formed during the peroxide-ceric ion reaction, butwhether this is compleved is ~nkn0~11.198Reviews of six- and eight-membered ring systems in sulphur chemistry lg9and of compounds containing sulphur-fluorine bonds 200 have been published.Sulphur reacts with lithium borohydride in ether, forming hydrogen,lithium sulphide, and a salt of formula LiB3S,H,; it is suggested that thiscompound contains an anion of structure ( 7 ) :Ig3L.Kolditz and D. Wass, 2. anurg. Chem., 1960, 307, 290, 304.lg4 G. S. Harris, Proc. Chem. Sue., 1961, 65.lS5 B. L. Chamberland and A. G. MacDiarmid, J., 1961, 445; J. Airier. Cfzein. SOC.,1961, 83, 549.lg6 E. Amberger, Ber., 1961, 94, 1447.lg7A. V. Grosse, A. G. Streng, and -4. D. Kirshenbaum, J . Amer. Chem. Suc., 1961,83, 1004.lgaM. Anbar, J . Anzer. Clzeni. SOC., 1961, 83, 2031; N. Anbar and S. Guttmann,ibid., p. 2035; E. Saito and B. H. J. Bielski, ibid., p. 4467.ls9 M. Becke-Goehring, Angew. Chem., 1961, 73, 589.200H. L. Roberts, Quart. Rev., 1961, 15, 30100 INORGANIC CHEMISTRYIn the absence of solvent, reaction takes place above 200°, and hydrogen andlithium dithioborate, LiBS,, are formed.201Sulphur tetrafluoride has been shown to be a very useful fluorinatingagent, converting mixtures of alkali metal or silver or thallous fluorides andmetal oxides, sulphides, or carbonyls into complex fluorides.202 It is alsouseful for the fluorination of uranium and plutonium oxides.,03 Adductsformed by sulphur tetrafluoride and boron trifluoride, arsenic pentafluoride,or antimony pentafluoride have been further described ; selenium tetra-fluoride displaces the sulphur compound from such adducts, and alsodisplaces bromine trifluoride from the adducts which the last compoundforms with auric fluoride and platinum tetrafl~oride.~~~ Man additionreactions of sulphur chloride pentafluoride to olefins and fluoro-olefinshave been described ; 205 reactions of fluoro-olefins with sulphur trioxidehave also been studied.206 Trifluoromethyl hypofluorite, CF,OF, reactswith sulphur trioxide at 250 O, forming trifluoromethyl peroxyfluorosulphon-ate, CF,-O*O-SO,F ; with sulphur dioxide, several products are formed,amongst them CP,*O*SO,F, CF,*O*SO,*O*CF,, CF,*O*SO,~O*SO,F, andCF3*O*S0,*O*S02*O*CF,, all of which are decomposed by aqueous allCali,though at markedly different rates.207 The peroxy-compound SFF*O*O+3F5is made by the interaction of SF,*OF and SOP, or SOP,, or by ultravioletirradiation of the first compound; it reacts only slowly with bases or withpotassium iodide (from which it liberates iodine). A wide range of physicalevidence supports the peroxy-formulation. 208 Disulphur dichloride ionisesvery slightly into S2C1+ and C1- ions and has been studied as a solventsystem. 209Disulphuryl fluoride reacts with ammonia at low temperatures accordingto the equationS,O,F, + 2NH, + F.SO,*NH, + NH,*SO,F.Analogous reactions take place with amines.210 Tetrasulphuryl fluoride,S4011F2, has been isolated from the products of the interaction of boron tri-fluoride and oleum, and polysulphuryl fluorides up to S,0,,F2, all havingacyclic structures, have been shown to be present.211 Boiling sulphur tri-oxide reacts with potassium cyanide to yield, in addition to a potassiumpolysulphate, sulphur dioxide, and paracyanogen, disulphuryl isocyanate,and a new compound (CN),,2S03; for the last, which can be made also bydirect combination of cyanogen and sulphur trioxide, the structure-O,S*N+iC*CiN +*SO,- is postulated.212 A large number of adducts of201H.Noth and G. Mikulaschek, 2. unorg. Chew., 1961, 311, 241.2oaR. D. W. Kemmitt and D. W. A. Sharp, J., 1961, 2496.203 C. E. Johnson, J. Fischer, and M. J. Steindler, J. Amer. Chem. SOC., 1961,83, 1620.204N. Bartlett and P. L. Robinson, J., 1961, 3417, 3549.205 J. R. Case, N. H. Ray, and H. L. Roberts, J., 1961, 2066, 2070.206D. C. England, M. A. Dietrich, and R. V. Lindsey, J. Amer. Chem. SOC., 1960,207 W. P. van Meter and G. H. Cady, J . Amer. Chem. SOC., 1960, 82, 6005.208C. I. Merrill and G. H. Cady, J. Amer. Chem. SOC., 1961, 83, 298.zoaH. Spandau and H. Hattwig, 2. unorg. Chem., 1961, 311, 32.210R. Appel and G. Eisenhauer, 2. unorg. Chem., 1961, 310, 90.211A. Simon and R.Lehmann, 2. anorg. Chem., 1961, 311, 224; R. J. Gillespie,212 H.-A. Lehmann, L. Riesel, K. Hohne, and E. Maier, 2. aizorg. Chem., 1961,310,298.82, 6181.J. T’. Oubridge, and E. A. Robinson, Proc. Chem. SOC., 1961, 428SHARPE: TYPICAL ELEMENTS 101sulphur trioxide and tertiary phenyl and cyclohexyl derivatives of Group Velements have also been reported.213 X-Irradiation of dithionites resultsin the formation of SO2- radical-ions which remain trapped in the lattice.ls8Tertiary phosphines react with tetrasulphur tetranitride according to theequationDiselenium dichloride reacts forming ( SeS2N2)C1,, 215 and potassium indimethoxyethane gives successively the S4N4-, S4N42-, S4NP3-, and S4N44-ions.216 The imide S7NH gives a substitution product S7N*BC12 on treat-ment with boron trichloride in carbon disulphide at -40°.217The decomposition of the oxyfluoride Se02P2 by ammonia yields a mix-ture of ammonium salts of cyclic triselenimide and of a series of poly(imid0-selenic acids) (e.g.the acid HO*Se02*NH*Se02*NH*Se02*OH) ; several othersalts have also been prepared.218Group VII.-Recent reviews have dealt with molecular complexes ofthe halogens, 219 the structures of interhalogen compounds and polyhalides,220halogen nitrates,221 polyfluoroalkyl compounds of metalloids and non-metals,222 and the physical and chemical properties of chlorine t r i f l ~ o r i d e . ~ ~ ~Work on liquid hydrogen halides as solvents has been continued,62* 224and it has been shown that Ph,N, Ph,As, Me20, Me2S, Ph,CCl, Ph,P, andPh,As can function as bases towards boron trichloride or methanesulphonicacid in liquid hydrogen chloride.By the action of bromine trifluoride on dinitrogen pentoxide in a Freonsolvent at low temperatures, bromine trinitrate, &(NO,),, is obtained;iodine reduces it to the mononitrate, which can also be obtained by the inter-action of bromine chloride and chlorine nitrate.Ozone converts it into thecompound BrO,*NO,, which is in turn converted by nitryl fluoride into theoxy!luoride Br0,F and dinitrogen ~ e n t o x i d e . ~ ~ ~ Some new compounds ofbromine, iodine, binary interhalogens, or positive halogen compounds witharomatic and heterocyclic bases have been prepared, and their infraredspectra have been studied.226 New polybromides of cobaltammines havealso been reported.227 Mixtures of stoicheiometric proportions of iodineRJ? + S,N, + R$'NIS, + S.213M.Becke-Goehring and H. Thielemann, 2. anorg. Chem., 1961, 308, 33,214H.-L. Krauss and H. Jung, 2. Naturforsch., 1961, 16b, 624.H. Garcia-Fernandez, Bull. Soc. chim. France, 1961, 1021.%lsD. Chapman, R. 31. Golding, A. G. Massey, and J. T. Moelwyn-Hughes, Proc.217H. G. Heal, J. Inorg. Nuclear Chem., 1961, 20, 165.218A. Engelbrecht and F. Clementi, Monatsh., 1961, 92, 555, 570.219 L. J. Andrews and R. M. Keefer, Adv. Inorg. Chem. Radiochem., 1961, 3, 91.220 E. H. Wiebenga, E. E. Havinga, and K. H. Boswijk, Adv. Inorg. Chem. Radio-221 M. Schmeisser and K. Brandle, Angew. Chena., 1961, 73, 388.222 R.E. Banks and R. N. Haszeldine, Adv. Inorg. Chem. Radiochem., 1961, 3, 338.223Y. D. Shishkov and A. A. Opalovskii, Uspekhi Khim., 1960, 29, 760 [357].224M. E. Peach and T. C. Waddington, J., 1961, 1238; F. Klanberg and H. W.Kohlschiitter, 2. Naturforsch., 1961, 16b, 69.225 hl. Schmeisser and L. Taglinger, Ber., 1961, 94, 1533.226 R. A. Zingaro and W. B. Witmer, J. Phys. Chem., 1960, 64, 1705; R. D. Whit-aker, J. R. Ambrose, and C. W. Hickman, J. Inorg. Nuclear Chem., 1961, 17, 254;A. I. Popov, J. C. Marshall, F. B. Stute, and W. B. Person, J. Amer. Chem. SOC., 1961,83, 3586.227 N. I. Lobanov and 0. S. Konovalenko, Zhur. neorg. h-hini., 1960, 5, 847 [407].Chem. Soc., 1961, 377.chem., 1961, 3, 133; R. E. Rundle, Acta Cryst., 1961, 14, 685102 INORGANIC CHEMISTRYpentafluoride and iodine, or bromine trifluoride and bromine, act as sources ofthe monofluorides for addition to fluoro-olefhs.228New molecular complexes of iodine which have been reported includethose with hydrogen ~ u l p h i d e , ~ ~ ~ amides, diethyl sulphide, and diethyl di- 'sulphide.230 The monosulphide is a much better donor than the disulphide,an order analogous to that obtained for diethyl ether and di-t-butyl per-oxide.The infrared and Raman spectra for some of the simpler polyhalideions have been presented and force constants have been calculated. Fortrihalide ions the stretching force constants are only about one half of thosein the free halogens, and it is concluded that the rather weak bonds in theseions are best considered as involving only p orbitals.231 The complex py,212has been shown to contain centrosymmetric, almost planar py21+ ions; theanion I,- is a loose complex of I,- and Z12.232 A wide range of evidenceleads to the conclusion that the blue solutions obtained when iodine or iodinemonochloride is dissolved in 65% oleum, lOOyo sulphuric acid, or fluoro-sulphonic acid contain I+ ions.The effective magnetic moment of 1-5 B.M.per gram-atom of iodine is attributed to the possession of the electronicstructure 5s25p4 by the cation, with a large crystal field stabilisation andsplitting of the electronic levels by the surrounding solvent.233The stabilities of the 1,Cl- and E l 2 - ions in aqueous media have beeninvestigated, and the latter has been shown to be much the more stable.When iodine trichloride is dissolved in aqueous hydrochloric acid, the ICI, -ion is not formed, and the reaction2IC1, + 3H,O --+ 10,- + IC1,- + 4C1- + 6H+takes pla~e.23~ Alkaline solutions of iodine have been shown to containthe &OH- i0n:235 k for the reactionI, + H20 -+ 1,OH- + H+is estimated as one hundred times greater than that forI, + H,O--+HOI + I- + H+.The salt NHiCrIO,, obtained from iodic acid and ammonium dichromate,contains a CrI0,- ion consisting of a CrO, tetrahedron sharing one oxygenatom with a IO, pyramid.236The preparation of astatine from the products of the action of high-energy protons on thorium has been described; it is said that, contrary toearlier statements, sulphur dioxide reduces oxidised forms of astatine onlyto the element.237 The existence of polyhalide ions containing astatine228R. D.Chambers, W. K. R. Musgrave, and J. Savory, Proc. Chem. SOC., 1961,229 J. Jander and G. Turk, Angew. Chem., 1961, 73, 63.2 3 0 H . Tsubomura and R. P. Lang, J. Amer. Chem. SOC., 1961, 83, 2085.231W. B. Person, G. R. Anderson, J. N. Fordemwalt, H. Stammreich, and R.2 3 2 0 . Hassel and H. Hope, Acta Chem. Scand., 1961, 15, 407.233 J. Arotsky, H. C. Mishra, and M. C . R. Symons, J., 1961, 12.234D. L. Cason and H. M. Neumann, J . Amer. Chem. SOC., 1961, 83, 1823.235 J. Sigilla, J . Chim. phys., 1961, 58, 002.236K. Wilhelmi and P. Lofgren, Acta Chem. Scand., 1961, 15, 1413.237 M. Lefort, G. Simonoff, and X. Tarrago, Bull.SOC. chim. France, 1960, 1726.113; J., 1961, 3779.Forneris, J . Chem. Phys., 1961, 35, 908SHARP: THE TRANSITION ELEMENTS 103(e.9. At1,-, AtIBr-, AtC1, --) has been dem~nstrated,~~s and the solutionchemistry of astatine has been expressed in a new potential diagram 239At--At- HOAt(?)- AtO,- H,AtO,( ?)-0-3 -1.0 - 1.5 < -1.6 VA. G. S.3. THE TRANSITION ELEMENTSTHE transition elements will be considered in an order similar to that adoptedlast year. General reviews published during the year include articles onthe borides and silicides of the transition elements,l on the dissociationenergies of gaseous metal dioxides,2 and on the uses of electron-spinresonance as applied to crystalline transition-metal compounds. In ageneral paper, the Kapustinskii formula has been used to calculate thelattice energies and enthalpies of formation of the transition-metal halidesMX, MX,, and MX, from scandium to zinc.It is shown that, from thethermodynamic viewpoint, several hitherto unknown halides should becapable of existence.An extremely important new book gives themathematical approach to the theory of transition-metal ions, and thequalitative applications are dealt with in two other books,6 one of whichis designed as an introductory text for students.‘ The Tilden lecture ofthe Chemical Society has dealt with the electronic configurations and struc-tures of transition-metal complexes * and there has been a general review onthe complexing of metallic cation^.^ More specialised reviews have dealtwith the chemistry of inner complexes,10 oxalato-complexes,ll complexesof biguanides and guanylureas,12 and with polymeric chelate compounds.l3Current experimental work suggests that greater emphasis must be givento n bonding when all types of complex are being considered. A study ofthe stability constants of some chromium(n) and vanadium(=) complexeshas been interpreted as showing that n bonding has a greater influence onthe stabiLity of complexes derived from cations in the first half of the firstComplexes.-( a) General.23*E. H. Appelman, J. Phys. Chem. 1961, 05, 325.239 E. H. Appelman, J . Amer. Chem. SOC., 1961, 83, 805.IB. Aronsson, ArEiv Kemi, 1961, 16, 379.eL. Brewer and G. M. Rosenblatt, Chem. Rev., 1961, 61, 257.3A. Carrington and H.C. Longuet-Higgins, Quart. Rev., 1960, 14, 427.*M. Barber, J. W. Linnett, and N. H. Taylor, J., 1961, 3323.ti J. S. GrifEth, “ The Theory of Transition Metal Ions,” Cambridge Univ. Press,L. E. Orgel, “ An Introduction t o Transition Metal Chemistry,” Rlethuen,7 D. P. Graddon, “ An Introduction to Co-ordination Chemistry,” Pergamon,sR. S. Nyholm, Proc. Chem. SOC., 1961, 273.London, 1961.London, 1960.London, 19G1.G. Schwarzenbach, Adv. Inorg. Chem. Radicchem., 1961, 3, 257.lo B. 0. West, Rev. Pure Appl. Chem. (Australia), 1960, 10, 207.l1 R. V. Krishnamurty and G. M. Harris, Chem. Rev., 1961, 61, 213.l2P. Rgy, Chem. Rev., 1961, 61, 313.laA. A. Berlin and N. G. Matveeva, Uspekhi Khim., 1960, 29, 277 [119].** The page number of the English translation of Russian chemical journals is givenin brackets104 INORUANIC CHEMISTRYrow of the transition series than from those in the second half (manganese tozinc).An immediate consequence of this is that the stability sequence forhigh-spin dipositive complexes of the first part of the transition series isligand-dependent . l4 The interpretation of absorption spectra of copper( II),copper(r), and iron(=) complexes requires a relative emphasis of the effectsof n and cr bonding Merent from that for the interpretation of stabilitydata.l5 The influence of crystal-field stabilisation is considered to have aneffect on adsorption a t a surface. The adsorption of oxygen on nickel oxidecompletes the octahedral field for the surface nickel atoms, and the oxygen isphotodesorbed on irradiation with light of a wavelength corresponding tothe chi! transitions in nickel oxide.The photodesorption is believed to pro-ceed by excitation of the nickel atom, desorption, and assumption of a tetra-hedral configuration with greater crystal field stabilisation.16 Further physi-cal studies have been made on the trans-effect in planar complexes. Nuclearmagnetic resonance shifts for the 18 protons in pyridine-platinum complexescan be interpreted in terms of n bonding between the metal and the halogenin the transposition relative to the pyridine, but kinetic studies of thedisplacement of halogen in complexes [MClR(PR’,),] (M = Ni, Pd, Pt;R = R’ = alkyl, aryl; R = hydrogen) can only be interpreted in terms ofboth polarisation and n b0nding.l‘ A study has been made of the thermo-dynamics of co-ordination at the sixth position in di(pentane-2,4-diono)oxo-vanadium(rv). The entropy change is greater than that measured for com-parable processes in solution but is considered to be a true entropy of co-ordination; it bears little relation to the chemical properties of the ligand.18Previous studies on the exchange of [ 15N]ammonia between aqueous ammo-nia and the ligands in metal ammines have indicated slow exchange, butrecent work on copper, silver, nickel, and aluminium ammines has indicatedrapid exchange with half-lives for the exchanges varying between 0.3 and3 sec.19 An extensive survey of the compounds MX,py, (X = halogen,py = pyridine) by various physical methods has shown that the co-ordina-tion about the metal may be tetrahedral, octahedral, or square planar; theinfrared spectra of these and other pyridine complexes are considered toindicate considerable back bonding from the metal to the pyridine.20 Theoxidation-reduction potentials of Cu(~)-Cu(n) complexes of substitutedderivatives of 2,2’-bipyridyl and o-phenanthroline are not related to theacid dissociation constants of the protonated ligands but to the co-ordinationnumber of the metal which is, in turn, related t o the bulk of the ligand.21The reduction of aryl nitro-derivatives by sodium borohydride is strongly14 J.M. Crabtree, D. W. Marsh, J. C. Tomkinson, R. J. P. Williams, and W. C.Fernelius, Proc. Chem.SOC., 1961, 336.15B. R. James, M, Parris, and R. J. P. Williams, J., 1960, 4630.l6 J. Haber and F. S. Stone, Proc. Chem. SOC., 1961, 424.1’A. D. Westland and L. Westland, Canad. J . Chem., 1961, 39, 324; F. Basolo,18R. T. Claunch, T. W. Martin, and M. 31. Jones, J . Amer. Chenz. Soc., 1961, 83,10 J. R. Sutter and J. P. Hunt, J . Amer. Chem. SOC., 1060, 82, 6420.20N. S. Gill, R. S. Nyholm, G. A. Barclay, T. I. Christie, and P. J. Pauling, J.Inorg. Nuclear Chem., 1961,18, 88; N . S. Gill, R. H. Nuttall, D. E. Scaife, and D. W. A.Sharp, ibid., p. 79.J. Chatt, H. B. Gray, R. G. Pearson, and B. L. Shaw, J., 1961, 2207.1073.21B. R. James and R. J. P. Williams, J . , 1961, 2007SHARP: THE TRANSITION ELEMENTS 105catalysed by transition-metal derivatives.When [Cobipy,13 + (bipy = 2,2'-bipyridyl) is acting as catalyst it is considered that [Cobipy,] + is the effectivereducing agent.22 In a series of octahedral complexes the degeneracy ofthe tzg orbitals can be removed in certain circumstances by the effect ofstrong n bonding and the diamagnetism of [Tiphen,1° (phen = o-phen-anthroline) is due to this orbital ~plitting.,~ Malonaldehyde (1) and formyl-R,acetone (2) complexes of chromium(rn) have been prepared by what ap-pears to be the general method of adding a mixture of chromium(=) andchromium(m) salts to a donor solvent containing an ionic salt of the ligand.Malonaldehydato-complexes are the simplest members of the series of,!Miketone complexes.24 The magnetic properties of many series of saltshave been systematically studied and of particular importance is the workon d3, d4, and tgg c0mplexes.2~ The magnetic susceptibilities of bi-nuclear complexes of iron and chromium with one, two, or three bridginggroups have been interpreted in terms of magnetic exchange between thepairs of metal atoms.26 From a study of infrared spectra it is concludedthat there is as much back bonding in isocyanide complexes as in carbonyls;for complexes of zero-positive metals this effect is so great that the isocyanidegroup becomes bent.27 Complexes have now been prepared for which infra-red spectra indicate bidentate sulphito- and sulphato-groups. The com-plexes [Co en,SO,]X (en = ethylenediamine; X = ClO,, NO,, I, SCN) and[ Co en2S04]X (X = Br, C10,) contain the bidentate ligands but in complexesof the types [Co en,(SO,)(H,O)]+ and [Co en,(SO,)X]+ the sulphato- andsulphito groups are unidentate (for a further example of a bidentate sulphategroup see ref.27a).28 Infrared spectra can also be used to distinguishbetween the various types of bonding possible with a perchlorate group.Most perchlorato- complexes contain the unidentate ligand but anhydrouscupric and ferric perchlorates may contain bidentate perchlorate groupings.29The infrared spectra of a number of metal acetylacetonates have been studiedin detail but it has proved difficult to come to conclusions about the natureof the metal-oxygen bonds because of the coupling of the M-0 vibrationswith the other vibrations in the molecule.Crystal-structure studies of theisomorphous aluminium, chromium, and cobalt derivatives show that.22 A. A. VlEek and A. Rusina, Proc. Chem. Soc., 1961, 161.23 L. E. Orgel, J., 1961, 3683; R. Perthel, 2. phys. Chem. (Leipxig), 1959, 211, 74.24 J. P. Collman and E. T. Kittleman, J. Amer. Chern. SOC., 1961, 83, 3529.25 A. Earnshaw, B. N. Figgis, J. Lewis, and R. D. Peacock, J . , 1961, 3132; B. N.Figgis, J. Lewis, and F. E. Mabbs, J., 1961, 3138; B. N. Figgis, Trans. Paraday SOC.,1961, 5'7, 204.z s A . Earnshaw and J. Lewis, J., 1961, 396.27 F. A. Cot,ton and F. Zingales, J . Arner. Chem. SOC., 1961, 83, 351.zsaC. K. Prout and H. M. Powell, J., 1961, 4177.28 C. G. Barraclough and M. L. Tobe, J., 1961, 1993; M. E. Baldwin, J . , 1961, 3123.2s B.J. Hathaway and A. E. Underhill, J., 1961, 3091; cf. 33. M. Jones, E. 9.Jones, D. F. Harmon, and R. T. Semmes, J . Anzer. Chem. Soc., 1961, 83, 2038106 INORGANIC CHEMISTRYthere are very similar atomic separations in all of these complexes and arenot in favour of theories which would relate the electron density inthe chelate ring to the number of d-electrons present or the number ofd-orbitals available on the metal atoms.30 Trends in the infrared spectraof complex chlorides run parallel to those observed for other metal-ligandvibrations.31Substitution reactionshave been reviewed 32 and the full report has been published of a FaradaySociety Discussion on oxidation-reduction processes in ionising solvents. 33The reactions of the reducing agent V2faq.with oxidising agents RL(R = Co111(NH3),; L = OH,, NH,, C1) have been found to proceed throughan outer-sphere complex rather than a bridged complex as is found whenCr2+aq. is used as the reducing agent. This difference in mechanism isrelated to the fact that in the case of V2+ it is a t2, electron which is beingtransferred and that the orbital can overlap with an orbital of the oxidant;in the case of Cr2+ the electron to be transferred is in an eg orbital whichis poorly situated for overlap with a receiving orbital and the electron mustbe transferred by way of a bridge.34 When the reducing agent is Crz-taq.and L is a half-ester, the attack is on the adjacent carboxyl group in allcases except for the hydrogen fumarate and methyl fumarate (half ester) andthe terephthalate where the ligand contains a conjugated double bond.Inthese cases there is 'attack at the remote end and a simultaneous protonattack on the near carboxyl group which aids conjugation in the ligand;ester hydrolysis occurs at the same time as the oxidation-reduction process.When L is hydrogen or methyl maleate there is isomerisation t o fumaricacid ; the ester hydrolysis occurs through alkyl-oxygen fission rather thanby acyl-oxygen fission as is more normally observed in ester hydrolysis.Replacement of the methylene hydrogens by ethyl groups shows that forthe (hydrogen maleato) -complex the methylene hydrogens are dissociatedin the intermediate state; this dissociation gives rise to more ready charge-transfer through the ligand.35 The rate of hydrolysis of halogenopentam-minechromium(m) ions is increased by the presence of sodium salts of weakacids and it is suggested that ion-pair formation with partial charge-transferhelps to maintain an octahedral configuration in the transition state.36Direct oxygenation of Cr2+ in ammoniacal solution to give binuclear species[ (NH3),Cr*O*Cr(NH3),1* + occurs by way of the peroxy-bridged complex[ (NH3),Cr*02*Cr(NH3),]*+ and the chromium(Iv) ion [ (NH3),Cr1v(OH)]3 +.37Acid cleavage of tetra-t-butoxychromium(1v) is of the Cr-0 bond; this(b) Mechanisms of reactions of inorganic complexes.'3O J.P. Dismukes, L. H. Jones, and J. C. Bailar, jun., J. Phys. Chem., 1961, 65,792; K. Nakamoto, P. J. McCarthy, A.Ruby, and A. E. Martell, J . Amer. Chem. SOC.,1961, 83, 1066; E. A. Shugam and L. M. Shkol'nikova, Doklady Akad. Nauk S.S.S.R.,1960, 133, 386.31D. M. Adains, Proc. Chem. SOC., 1961, 335.32 F. Basolo and R. G. Pearson, Adv. Inorg. Chem Radiochem., 1961, 3, 1.33 Discuss. Paraday SOC., 1960, 29.34A. Zwickel and H. Taube, J. Amer. Chem. Soc., 1961, 83, 793.35 D. K. Sebera and H. Taube, J. Amer. Chern. SOC., 1961,83, 1785; R. T. M. Fraser36T. P. Jones, W. E. Harris, and W. J. Wallace, Canad. J. Chem., 1961, 39, 2371.37 T. B. Joyner and W. K. Wilmarth, J. Amer. Chein. SOC., 1961, 83, 516.and H. Taube, ibid., pp. 2239, 2242; G. Svatos and H. Taube, ibid., p. 4172SHARP: THE TRANSITION ELEMENTS 107agrees with the postulated mechanism for the oxidation by chromium(v1)of organic derivatives as proceeding through a chromium(1v) alkoxide withretention of configuration.38 The initial step in the oxidation of manga-nate( VI) to permanganate(m) by hypochlorite is disproportionation tomanganate(v) and permanganate( VII) ; the subsequent oxidation of manga-nate(v) to permanganate(vr1) is slow.39 Ligands in which oxygen is bondedto the metal increase the rate of uptake of molecular oxygen by iron(n)solutions whilst nitrogen-containing ligands have no such effect.It ispostulated that n bonding in the former complexes increases the electrondensity in the iron(n) tzs orbitals and favours electron transfer to a co-ordinated dioxygen molecule but that such n bonding does not occur inthe nitrogen c~mplexes.~O Since the rate of oxidation of iron(@ ions byiron(m) complexes of substituted o-phenanthroline, 2,2'-bipyridyl, and2,2,2"-terpyridine derivatives is related only to the basicity of the ligandsand is not influenced by steric effects it is suggested that electron transferdoes not take place with the reducing agent at the periphery of the iron(nr)complex but that the iron@) must penetrate between the ligands and makealmost direct contact with the iron(m), a mechanism similar to that envisagedfor the reductions by V2 +aq.mentioned above. 41 The propylenediamine-tetra-acetatocobaltates(n and 111) both exist almost exchsively in the formof one enantiomer and electron transfer between the two species takes placewith complete retention of configuration for both species.Substitution ofother chelating agents into et hy lenediamine - and prop y lenediamine - t etr a -acetato-complexes also occurs with retention of c0nfiguration.4~ Thephotochemically initiated redox and substitution reactions of some cobalt(II1)and chromium(m) complexes have been discussed in terms of two mechan-isms. The first is activation by electronic excitation and the second involvescharge transfer in and subsequent fission of a metal-ligand bond. Thelatter theory is favoured by experiments with light of different energies;for light of short wavelengths both aquation and reduction should takeplace with high quantum yield but long-wavelength radiation should giveonly ionic dissociation ; both predications are in accord with ob~ervation.~~Substitution of nitrite into chloroplatinum(1v) ammines occurs by way ofa slow reduction of platinum(1v) to platinum(I1) followed by a two-electronoxidation involving a bridged intermediate.The necessity for the bridgedintermediate can be used to explain the impossibility of substituting morethan five nitro-groups into the PtClG2- The exchange reaction be-tween mercury aryls and alkyls, HgRR', and mercuric halides, HgX,, is38K. B. Wiberg and G. Foster, Chem. and Ind., 1961, 108.39 M. W. Lister and Y. Yoshino, Canad. J. Chem., 1961, 39, 96.40T. Kaden and S. Fallat, Helv. Chim. A d a , 1961, 44, 714.41M. H. Ford-Smith and N. Sutin, J. Amer. Chem. Xoc., 1961, 83, 1830.42 F. P. Dwyer and F. L. Garvan, J.Amer. Chem. SOC., 1961, 83, 2610; Y. A. Imand D. H. Busch, ibid., p. 3362; H. Irving and R. D. Gillard, J., 1960, 5266; 1961,2249; cf. S. Kirschner, Y.-K. Wei, and J. C. Bailar, jun., J. Smer. Chem. Xoc., 1957, '79,5877.43 H. L. Schlafer, 2. Elektrochem., 1960, 64, 887; A. W. Adamson, Discuss. FaradaySOC., 1960, 29, 163; Z. Simon, Canad. J. Chem., 1960, 38, 2373.44H. R. Ellison, F. Basolo, and R. G. Pearson, J. Amer. C'irem. SOC., 1961, 83,3943; I. I. Chernyaev, L. A. Nazarova, and A. S. Mironova, Zhur. neorg. Khim., 1959,4, 747 [340]108 INORGANIC CHEMISTRYbelieved to take place through an intermediate (e.g., 3) in which mercury istaking part in two three-centre bonds.45(c) Curbonyls. Technetium carbonyl, Tc,(CO),,, hasnow been prepared by the action of carbon monoxide on\ / Tc20,; it reacts with iodine to give [Tc(CO,)I], whichSomenew reducing agents have been described which are claimedto be effective in reductive carbonylation reactions ; sodium in diethyleneglycol dimethyl ether (diglyme) and zinc dust in ether or dichloroethane areeffective in producing Group VI ~arbonyls.~' The elusive Mn2(C0),, can beprepared in good yield by the action of carbon monoxide and sodium indiglyme on n-methylcyclopentadienylmanganese tricarbonyl.,* The ex-change reactions of metal carbonyl derivatives have been examined in somedetail.Group VI hexacarbonyls do not undergo exchange with labelled car-bon monoxide in the dark but there is rapid exchange under the influence ofultraviolet light.The exchange appears to occur by wa.y of dissociationto give M(CO), intermediates ; the interaction of these intermediates withother ligands is an ideal method for the preparation of substituted car-bonyls.,g Nickel and cobalt carbonyls also undergo exchange of carbonmonoxide by dissociative mechanisms : for dicobalt octacarbonyl all of thecarbonyl groups are equivalent with respect to exchange. Mn(CO),Xderivatives undergo exchange of both carbon monoxide and X by flxlmechanisms but Fe(CO),I, exchanges carbon monoxide by an XNl mechan-ism and iodine by an 8,2 mechanism. n-Cyclopentadienylmetal carbonylsgenerally undergo exchange of carbon monoxide by EX2 mechanisms. 5OSome reactions of vanadium hexacarbonyl have now been reported.With triphenyl-phospine , -arsine, and -stibine it gives substituted complexesL2V( CO), ; the phosphine complex is reduced to the [V-l(CO),(Ph,P>] -anion by sodium amalgam.Nitrogen and oxygen bases cause dispropor-tionation to give salts [V11L,][V-1(CO)6], (n = 4 or 6); on acidification theanions give the hydrides V(CO),H and V(CO),(Ph,P)H.51 The salts[Nadiglyme,][M(CO),] (M = V, Nb, Ta) are prepared in good yield by theaction of carbon monoxide and excess of sodium in diethylene glycoldimethylether on the metal pentahalides. Phosphoric acid converts the hexacar-bonylvanadate( -I) t,o vanadium hexacarbonyl in good yield but niobiumand tantalum carbonyls have yet to be isolated. 52 Iodopentacarbonyl-CIEt / Hg\phc , Hg (3) gives Tc(CO),I with excess of carbon rn~noxide.~,45 R.E. Dessy, Y. K. Lee, and J.-Y. Kim, J . Amer. Chem. SOC., 1961, 83, 1163;0. A. Reutov and G. M. Ostapchuk, Zhur. obshchei Khim., 1959, 29, 1614 [1588].46 J. C. Hileman, D. K. Huggins, and H. D. Kaesz, J . Amer. Chem. Soc., 1961, 83,2953; cf. W. Hieber and C. Herget, Angew. Chem., 1961, 73, 579.47 H. E. Podall, H. B. Prestridge, and H. Shapiro, J . Amer. Chem. SOC., 1961, 83,2057; V. L. Volkov, E. P. Mikheev, K. N. Anisimov, L. E. Eliseeva, and Z. P. Valueva,Zhw. neorg. Khim., 1958, 3, 2433.4aH. E. Podall and A. P. Giraitis, J . Org. Chem., 1961, 26, 2587.4eTV. Strohmeier and R. Muller, Z . phys. Chem. (Frankfurt), 1961, 28, 112.50F. Basolo and A. Wojcicki, J . Amer. Chem. SOC., 1961, 83, 520; A. Wojcickiand F. Basolo, J .Irwrg. Nuclear Chem., 1961, 17, 77; W. Hieber and K. Wollman,Chem. Ber., 1961, 94, 305.s1 W. Hieber, J. Peterhans, and E. Winter, Chent. Ber., 1961, 94, 2572; R. P. M.Werner, 2. Naturforsch., 1961, 16b, 477.52 R. P. M. Werner and H. E. Podall, Chem. and I?id., 1961, 144SHARP: THE TRANSITION ELEMEXTS 109chromates(0) react with iodine to give Cr(CO),I. This blue compoundinsoluble in water is the first carbonyl halide of a Group VI element.53Chromium and molybdenum carbonyls react with sodium borohydride inammonia and &ethylene glycol dimethyl ether to give Na,M,(CO),, andNa,M,(CO),, in the two solvents, respectively; the pentacarbonylchromate-(-11) anion can be oxidised by water to the [Cr,(CO),,H]- ion.5* Thereaction between metal carbonyls an'd sulphur trioxide yields what arebelieved to be pyrosulphato-complexes, (OC),MoO( SO,),, (OC),MnO(SO,),,and ( OC),FeO(S0,),.55 Metal carbonyl cations have been described for thefirst time; they are generally prepared by the action of excess of carbonmonoxide on a metal carbonyl halide in the presence of a strong Lewis acidsuch as aluminium chloride.Co-ordination of olefins or phosphines canalso stabilise the cation and examples of such substituted cations will befound elsewhere in this Report. The carbonyl cations described in the litera-ture during 1961 are [Mn(CO),]+, [Re(CO),]+, [Fe(Co),12+, and [os(Co)6]2+,all isoelectronic with the Group VI hexacarbonyls. 56 Dimanganese decacar-bony1 is reduced by sodium borohydride when in tetrahydrofuran solutionto give H,Mn,(CO),; this is the first binuclear carbonyl hydride of a metalof odd atomic number.,' The first example of a new class of compound isproduced when manganese carbonyl reacts with dinitrogen tetroxide to give&h(N03)(C0)5.5s Triphenylarsine was previously considered to react withmanganese carbonyl to give an adduct but this has now been identified as'an arsenide [Ph,AsMn(CO),],; the arsenic atoms act as bridges between thetwo manganese atoms, and there is no longer any necessity to postulatea inetal-metal bond.59 X-Ray studies show that the compounds describedin the older literature as enneacarbonyls, M,(CO), (M = Ru, 0s) are in facttrimetal dodecacarbonyls, M,(CO),,.Go Phosphinetricarbonylcobaltates( -I)are prepared by the action of sodium in tetrahydrofuran on the appropriatephosphinecobalt carbonyl.They give hydrides, HCo( CO),PR,, on acidifica-tion, and the sodium salt reacts with methyl iodide to give the methylderivatives Me*Co(CO),*PR,. 61 Cobalt carbonyls react with organic deriva-tives CX,Y [X = halogen; Y = Me, C1, F, Ph, CO,Et, CO,H, CH(OAc),,and CF,] to give complexes [Co,(CY)(CO),] of exactly the same type as resultfrom the treatment of acetylenehexacarbonyldicobalt complexes with acid. 62The cobalt carbonyl sulphide, Co,S(CO),, which is prepared by the actionof carbon monoxide on Co,S(CO),, has a similar stoicheiometry and mayhave a similar structure.63 Rhodium carbonyl chloride has a most unusualstructure (4) in which two planar Rh(CO),Cl units intersect a t an angle and63H.Behrens and H. Zizlsperger, 2. Nuturforsch., 1961, 16b, 349.s4H. Rehrens and W. Haage, Chem. Ber., 1961, 94, 312, 320.s5 R. P. M. Werner, Chem. Ber., 1961, 94, 1207.66 E. 0. Fischer and K. Ofele, Angew. Chem., 1961, 73, 551; W. Hieber and T.s7 W. Hieber, W. Beck, and G. Zeitler, Angeu-. Chem., 1961, 73, 364.58C. C. Addison, &.I. Kilner, and A. Wojcicki, J., 1961, 4839.59R. F. Lambert, Chem. and Ind., 1961, 830.soE. R. Corey and L. F. Dahl, J . Amer. Chem. Soc., 1961, 83, 2203.61 W. Hieber and E. Lindner, 2. Nuturforsch., 1961, 16b, 137.62W. T. Dent, L. A. Duncanson, R. G. Guy, H. W. B. Reed, and B. L. Sliaw,63L. Mark6, G. Bor, and E. Klumpp, Chem. and Id., 1961, 1491.Kruck, ibid., p, 580.Proc.Chem. Xoc., 1961, 169; cf. Ann. Zeports, 1960, 57, 148110 IN 0 RG AN I C CHEMISTRYBond lengths and angles in Rh(CO),Cl.(Reproduced with permission from J. Amer. Chem. SOC., 1961, 83, 1762.)are joined by two chlorine bridges, both on the same side of the line joiningthe two metal atoms. These dimers are linked by Rh-Rh bonds to forminfinite chains and a second, but this time bent, metal-metal bond is sug-gested in the dimers. This is formed by overlap of a-type orbitals a t anangle of 56" and such bent metal-metal bonds are suggested as a generalphenomenon in metal carbonyl c~mplexes.~~ Carbon monoxide at highpressures reacts with' K,IrBr, and K,IrCl, to produce a wide variety ofcarbonyl complexes which can be converted into one another by variouschemical processes. Anions of the types [Ir(CO),X,]2 -, [Ir,(C0)4X,] -, and[Ir2(C0),X2] are reported.65 The [Ni4(CO) J2- anion has previously beenshown to result from the reduction of nickel carbonyl with solutions of alkalimetals in liquid ammonia but ammonolysis can lead to a binuclear hydride,H2Ni2(C0),.66 Silver and mercuric salts are good catalysts for the oxidationof carbon monoxide.Carbon monoxide enters into reaction by insertionbetween the metal and the oxygen in an Ag-OH or Hg-OH, grouping (thelatter complex then loses a proton). Both of these processes are favouredby high pH and reaction occurs very readily in the case of the silver am-mines. Mercuric acetate reacts with carbon monoxide in methanol to give aseries of products, XHg*CO*OMe, which appear to be derived from the reac-tion of a mercury methoxide with carbon monoxide.67Nitric oxide reacts with V(CO), and V(CO),(Ph,P), togive V(CO),(NO) and V(CO),(Ph,P)(NO), respectively.Pentacarbonyl-nitrosylvanadium( -I) is isoelectronic with chromium he~acarbonyl.~~, 68 A64 L. F. Dahl, C. Martell, and D. S. Wampler, J. Amer. Chem. SOC., 1961, 83, 1761.G5L. Malatesta and F. Canziani, J. Inorg. Nuclear Chern., 1961, 19, 81.66H. Behrens and F. Lohofer, Chem. Ber., 1961, 94, 1391.67 J. Halpern and S. F. A. Kettle, Chem. and Ind., 1961, 668; A. C. Harkness andJ. Halpern, J. Amer. Chem. SOC., 1961, 83, 1258; S. Nakamura and J. Halpern, ibid.,p. 4102.6aR. P. M. Werner, 2. Naturforsch.. 1961, 16b, 478.(d) NitrosylsSHARP: THE TRANSITION ELEMENTS 111new nitrosylcarbonyl of manganese, Mn(CO),(NO), isoelectronic with ironpentacarbonyl, is prepared by the action of N-methyl-N-nitrosoto1uene-p-sulphonamide on manganese carbonyl hydride in ether.It is very sensitiveto oxidation and on irradiation with ultraviolet light gives Mn,(CO)7(N0),.69Iodotetracarbonyltriphenylphosphitomanganese reacts with nitric oxide togive two nitrosyls, [ (PhO),P]Mn(NO),, analogous to the nitrosyl preparedby the action of nitric oxide on the corresponding triphenylphosphine com-plex, and a new type of complex, [(Ph0)3P],Mn(NO)21.70 Many othersubstituted metal nitrosyls have been prepared by reaction of metal nitrosylhalides with ligands L such as triphenyl-phosphine, -arsine, and -stibine.They are of the types Fe(NO),LX, Fe(NO),L,, Co(NO),LX, Rh(NO)(R,P),,Rh(NO)(R,P),Cl,, [Ni(NO)LX],, and Ni(NO)L,X. The compound[Co(NO),Cl], reacts with tertiary phosphines in the presence of sodiumama,lgam to give Co(NO)L, derivatives ; the parent compoundJ Ni(NO),( Ph,P),,of the series of halogenonitrosylphosphinenickel complexes is prepared bythe action of nitric oxide on Ni(C0)2(Ph3P),.71 The range of iron(1r) andcobalt(=) salts that give nitrosyls by direct addition of nitric oxide hasbeen extended by the preparation of adducts with di( salicyla1dehydato)-dipyridineiron(n) ; diacido-di- (8-aminoquinoline)cobalt( 11) (chloride andnitrate) ; and di(histidino)cobalt(11).7~ K,Ru(NO)Cl, has a defarmed(NH3),FeF6 structure ; the Ru-N-0 grouping is linear.', Many nitrosyl-ruthenium species have been postulated to exist in solutions of nitrosyl-ruthenium in water and tributyl phosphate but only Ru(NO)(NO,),(H,O)~ haspreviously been isolated. However, new compounds, KRu(NO)(NO,),,H,Oand Ru(NO)(NO,),[ (BuO),PO],, have now been obtained from these solu-tions.74 [Co(NH,),(NO)]Cl reacts with potassium cyanide and water to giveK2[ HCo( CN)5(N0)],2H,0 which yields K3[ Co( CN),( N0)],2H20 with aqueouspotassium hydroxide.Water reconverts the [CO(CN),(NO)]~- anion intothe [HCo(CN),(N0)l2- ion. There is no information as to how the hydrogenis bonded in these species.75 The nitric oxide complexes of nickel, palla-dium, and platinum have been re-investigated and six- and four- co-ordinatedderivatives have been found.Nickel carbonyl reacts with nitric oxide andammonia in the presence of water to give [Ni(NO)(NH,),(OH)](OH),; inmethanol the same reaction gives [Ni(NO)(NH,)( OMe)( OH)]OH which isconverted into a hydroxy-complex with nitro-bridges when refluxed.Treatment of dipotassium tetranitropalladate(11) with nitric acid yieldsK2[Pd(NO)(N02),(N0,)]J and the platinum salt can be prepared similarly.Nitric oxide gives a green solution with aqueous dipotassium tetrachloro-platinate(rr), and a pyridine adduct [Ptpy2(N02)C1] can be isolated.69 P. M. Treichel, E. Pitcher, R. B. King, and F. G. A. Stone, J . Amer. Chem. SOC.,1961, 83, 2593.7 0 W. Hieber, W. Beck, and H. Tengler, 2. NatuTforsch., 1961, 16b, 68.i1 W.Hieber and K. Heinecke, 2. Naturforsch., 1961, 16b, 553, 554; W. Hieberand R. Kramolowsky, ibid., p. 555; W. Hieber and I. Bauer, ibid., p. 556; W. P.G r a t h , J. Lewis, and G. Wilhson, J., 1961, 2259.72 R. Nast and H. Riickemann, 2. anorg. Chem., 1961, 307, 309; R. Nast, H. Bier,and J. Gremm, Chem. Ber., 1961, 94, 1185; P. Silvestroni and L. Ceciarelli, J . Amer.Chem. SOC., 1961, 83, 3905.73T. S. Khodashova and G. B. Bokii, Zhur. strulct. Khim., 1960, 1, 161.54D. Scargill and J. M. Fletcher, Proc. Chem. SOC., 1961, 251.75R. Nast and R. Thome, 2. anorg. Chem., 1961, 309, 283112 INORGANIC CHEMISTRYNitrosyl chloride adds directly to four-co-ordinate platinum(n) complexesto give compounds of the type PtII(NO)L,, and nitric oxide reacts withtetrammineplatinum(x1) chloride in nitric or acetic acid to give complexesformulated as [ Pt(N0) (NH3)4( OAc)]Cl, or [ Pt( NO) ( NH3),(N0,)](N0,)C1.76Olefins can readily substitute into arenemetal car-bonyls and can sometimes stabilise a cation in the same manner as an extracarbonyl group. n-Mesitylenechromium tricarbonyl reacts with ethylene togive (n-C,H3Me3)Cr(C,H4)(~o)2,77 and metal carbonyl and n-cyclopenta-dienylmetal carbonyl halides react with aluminium halides in the presence ofethylene to give the cations [Mn(CO),(C,H,)] f, [ (n-C,H,)Fe(CO),(C,H,)] +,and [ (n-C,H,)M(CO),(C,H,)] + (M = Mo, W) which can be isolated in the formof stable salts.,,, 78 The z-ally1 complexes (n-C,H,)Fe(CO),(n-C3H4R)(R = H or Me) are protonated by hydrogen chloride or hydrochloric acidto give the propene analogues of the ethylene-iron complex mentionedabove.79 By varying both of the metals in the systems, R,MCl,, TCl,(R = alkyl, M = p-group metal, T = transition metal), which can be usedfor olefin polymerisations, it has been shown that the growing polymer, andhence the initial olefin, is attached to the transition metal.80 Olefin coin-plexes are considered to act as intermediates in reactions in which chloro-ruthenate(I1) solutions act as homogeneous catalysts for the hydrogenation ofolefins 81 and in the Meerwein reaction in which an aryldiazonium halideadds across the double bond of an olefin.82 Dimethylpent-4-enylarsineMe2As*[ CH,],*CH:CH, can act as a chelating agent by co-ordination throughthe arsenic and the double bond, and forms complexes with platinum(n);83however, vinyl sulphides undergo desulphurisation, and the products of thereaction between the vinyl sulphides RS*CH=CH2 and tri-iron dodeca-carbonyl are formulated as (5), a structure in which the vinyl group is actingas a bridge between the two iron atoms by way of a 7t and a u bond, theother half of the bridge being made up by the sulphur-containing residue.84(e) ObeJin compbexes.HMe Meo=c c=oH\ /* //c=q\H ,c=c,c=c' \ (OC),Fe -S J e ( c 0 ) 3 Me Me (6)R (5)Many new complexes of polyenes have been described and these will bementioned only where new principles are involved.A structurd deter-mination on butadieneiron tricarbonyl has confirmed that it is a n-bondcomplex with both double bonds taking part in the co-ordination.In fact,i 8 W. P. GrifEth, J. Lewis, and G. Wilkinson, J., 1961, 775.*"E. 0. Fischer and P. Kuzel, 2. Naturforsch., 1961, 16b, 475.78E. 0. Fischer and K. Fichtel, Chem. Ber., 1961, 94, 1200.7 9 M. L. H. Green and P. Nagy, Proc. Chern. SOC., 1961, 378.8oF. J. Karol and N. L. Carrick, J. Amer. Chem. SOC., 1961, 83, 2654.J. Halpern, J. F. Harrod, and B. R. James, J. Amer. Chcm. SOC., 1961, 83, 753.82 G. N. Schrauzer, Chem. Ber., 1961, 94, 1891.83 H. W. Kouwenhoven, J. Lewis, and R. S. Nyholm, Proc. Chem. Xoc., 1961, 220.84 R. B. King, P. M. Treichel, and F. G. A. Stone, J. Amer. Chem. SOC., 1961, 83,3600SHARP: THE TRANSITION ELEMENTS 113there is complete delocalisation of the n electrons from the formal dienestructure.s5 A new butadiene complex, [ (C4H6)C~(C0)2]2, has been shownto result from the action of butadiene on dicobalt octacarbonyl.86 m- andp-Divinylbenzenes react with iron pentacarbonyl to give bis( tricarbonyliron) complexes. The nature of these is not known, but the stoicheiometrysuggests that the divinylbenzenes are not using their full co-ordinatingcapacity of five double bonds but are co-ordinating through two diene groups.A similar co-ordinating capacity equal to two diene residues is found forvinylcy~loheptatriene.~~ Duroquinone (6) can act as a diene towards nickeland gives bisduroquinonenickel(0) when it reacts with nickel carbonyl.Cyclo-octatetraene displaces one duroquinone residue to give cyclo-octa-tetraeneduroquinonenickel(0).88 A structural determination on norborna-dienepalladium(r1) chloride has shown that both double bonds are co-ordinated to the metal ; 89 in cycloheptatrienemolybdenum tricarbonyl theC=C bonds in the ring have not become delocalised; the methylene group isout of the plane of the other carbon atoms, the carbonyl groups are on the sideof the metal opposite to the seven-membered ring. Cycloheptatrienereacts with iron pentacarbonyl to give cycloheptatrieneiron tricarbonyl ('7)in which the Fe(CO), residue is bonded to two adjacent double bonds, andcyclohepta-l,3-dieneiron tricarbonyl (8). The un-co-ordinated double bondin the cycloheptatriene complex can be readily protonated in acids or canreact with a triphenylmethyl cation to give carbonium ions (9) which arestabilised by co-ordination to the metal.Cyclo-octatetraeneiron tricarbonylis protonated similarly.Q1 Fulvene, with three double bonds, gives a varietyof products when it reacts with iron carbonyls. The two double bondsin the ring can act as a diene system to an Fe(CO), residue, and the iron atomand the remaining double bond can bond to yet another Fe(CO), grouping;alternatively each double bond can co-ordinate separately to Fe(C0)4 groups.6,6-Diphenylfulvene co-ordinates to a Cr(CO), residue by way of the aromaticrings. 92 The structure of cyclo-octatetraenedi-iron hexacarbonyl shows86 0. 8. Mills and G. Robinson, Proc. Chem. Soc., 1960, 421.8g E. 0. Fischer, P. Kuzel, and H. P. Fritz, 2.Naturforsch, 1961, 16b, 138.87 R. B. King and F. G. A. Stone, J . Amer. Chem. Soc., 1961,83,3590; T . A. Manuel,8 8 G.-N. Schrauzer and H. Thyret, J. Amer. Chenz. SOC., 1960, 82, 6420; 2. Natur-89 N. C. Baenziger, J. R. Doyle, and C. Carpenter, Acta Cryst., 1961, 14, 303.slA. Davison, W. McFarlane, L. Pratt, and G. Wilkinson, Chem. and Ind., 1961,553; R. Burton, L. Pratt, and G. Wilkinson, J., 1961, 594; H. J. Dauben, jun., andD. J. Bertelli, J . Amer. Chem. SOC., 1961, 83, 497; G. N. Schrauzer, ibid., p. 2966.s*E. Weiss and W. Hubel, Angew. Chem., 1961, 73, 298; E. 0. Fischer and W.Semmlinger, Naturwiss., 1961, 48, 525.S. L. Stafford, and F. G. A. Stone, ibid., p. 3597.forsch., 1961, 16b, 353.J. D. Dunitz and P. J. Pauling, Helv. Chim.Acta, 1960, 43, 2188114 INORGANIC CHEMISTRYthat the ring is in the form of a chair and that each iron tricarbonyl groupis associated with four carbon atoms in an arrangement (10) very similarto that found for butadieneiron tricarbonyl. Theequivalence of the protons is a dynamic effect.93As mentioned in last year’s Report, polyenes canundergo isomerisations with metal carbonyls andthen may give complexes which are apparentlyderived from olefins in which there are conjugateddouble bonds. Thus the two isomeric iron tri-carbonyl complexes which result from the inter-action of tri-iron dodecacarbonyl and cyclo-octa-trienes are complexes derived from the olefins bicyclo[4,2,0]octa-2,4-dieneand cyclo-octa- 1,3,5-triene ; 1,4-~yclopentadiene yields complexes that arederived from cyclopenta- lY3-diene ; and lY4-dihydromesitylene gives com-plexes derived from 1 ,3-dihydrome~itylene.~*The major recent advances in the study of olefin complexes have comein the recognition of further “ enyl ” derivatives of the transition metalsin which odd numbers of electrons are donated to the metal atom.Manyof these complexes were known previously but have now been re-formulated.Propenyl derivatives of manganese, cobalt, nickel, palladium, and platinum,in which the metal is further bonded to carbonyl, n-cyclopentadienyl, halide,phosphine, and other ligands, have been described. 5 9 96 Nuclear magneticresonance studies on solutions of some of these propenyl derivatives indimethyl sulphoxide suggest that in this polar solvent the complexes revertto classical o-bonded organometallic structures, the co-ordination spherebeing completed by the solvent. 96 The perfluoropropenyl group forms onlyo-bonded compounds.97 The “ enyl” group can be part of a ring, andformally the resonance and co-ordination stabilised carbonium ions describedabove 91 are part of this series.The complex which results from theaction of cyclopentadiene on nickel carbonyl is now recognised as n-cyclo-pentadienyl-n--cyclopentenylnickel( 11) and similar n-cyclopentenyl andn- cyclohexenyl derivatives have been prepared for nickel and palladium byreaction between the appropriate Grignard reagent and a metal halide orby interaction of dienes and metal carbonyl~.~~ The action of a mixtureof carbon monoxide and hydrogen on di-n-cyclopentadienylchroinium(n)gives n-cyclopentadienyl-n-cyclopentenylchromium(rr) dicarbonyl.lOO Theg3 B.Dickens and W. N. Lipscomb, J . Amer. Chem. SOC., 1961, 83, 489.s4T. A. Manuel and F. G. A. Stone, J . Amer. Ch,em. Soc., 1960, 82, 6240; J. E.Arnet and R. Pettit, ibid., 1961, 83, 2954; R. B. King, T. A. Manuel, and F. G. A.Stone, J . Inorg. Nuclear Chem., 1961, 16, 233; cf. Ann. Beports, 1960, 57, 146.95W. R. McClellan, H. H. Hoehn, H. N. Cripps, E. L. Muettertiss, and B. W.Howk, J . Amer. Chem. SOC., 1961, 83, 1601; R. F. Heck and D. S. Breslow, ibid., p.1097; E. 0. Fischer and R. D. Fischer, 2. Naturforsch., 1961, 16b, 475; E. 0. Fischerand G. Barger, ibid., pp. 77, 702; Chem. Ber., 1961, 94, 2409; H. P.Fritz, ibid., p. 1217;B. L. Shaw and K. Sheppard, Chem. and Ind., 1961, 517; R. F. Heck, J. C. W. Chien,and D. S. Breslow, ibid., 1961, 986.96 J. C. W. Chien and H. C. Dehm, Chem. and Ind., 1961, 745.97 R. B. King, S. L. Stafford, P. M. Treichel, and F. G. A. Stone, J . Amer. Chem.Sm., 1961, 83, 3604.99 D. Jones, G. W’. Parshall, L. Pratt, and G. Wilkinson, Tetrahedron Letters, 1961,48; E. 0. Fischer and H. Werner, ibid., p. 17; M. Dubeck and A. H. Filbey, J . Amer.Chem. Xoc., 1961, 83- 1357.Fe(C0)3Fe( CO) 3 4SHARP: THE TRANSITION ELEMENTS 115compound previously regarded as n-benzenecyclopentadieneiron(0) is nowregarded as n-cyclohexadienyl-n-cyclopentadienyliron(n) and n- 1 -en&-phenylcyclohexadienyl derivatives are obtained by the action of phenyl-di-n-benzenerhenium(1) cation is converted by hydrides to n-cyclohexadienyl-z-benzenerhenium(1) but reduction of the di-n-benzeneruthenium(1r) cationgives only the olefin complex (~-C,H,)RU(C,H,).~~~ In an unusual reactionwhich involves ring opening, n-tetramethylcyclobutadienenickel dichloridereacts with sodium cyclopentadienide to give n-cyclopentadienyl-n-dihydro-tetramethylindenylnickel(n) (1 1) .lo2 Butadieneiron tricarbonyl reacts withlithium on [ (n-C,H,)Mn(Co),][C1o*] and [ (n-C,H,)(n-C,H,)Fe]Br,.Thehydrogen chloride to give (12). Only one isomer is formed and it is suggestedthat the geometry of the original butadiene complex is retained in then-ally1 complex so that the methyl group is always in one position withrespect to the metal.lo3( f ) Acetylene complexes and reactions of transition-metal compounds withacetylenes.There will be no discussion in this section of the reactions ofacetylenes which have only been postulated to go by may of acetylenecomplexes. n-Cyclopentadienylmanganese tricarbonyl reacts with diphenyl-acetylene to give (n-C,H,)Mn(Ph*C=C*Ph)(CO)2 in which the acetylene isreplacing a carbonyl group in one co-ordination position.lo4 As mentionedin previous Reports a-aryl derivatives of the transition metals can tri-merise acetylenes to benzenoid compounds. After application of diphenyl-manganese(rr) or dimesitylcobalt(1r) to trimerise but-%yne, n-hexamethyl-benzene complexes of these metals can be is01ated.l~~ A crystal-structuredetermination has confirmed that the product from the reaction betweenmcyclopentadienylcobalt dicarbonyl and but-2-yne is n-cyclopentadienyl-tetramethylcyclopentadienonecobalt(I). The carbonyl group in the cyclo-pentadienone ring is tipped away from the metal; all the C-C bonds are ofequal length implying extensive delocalisation of the double bonds.Alarge range of products has been isolated as the result of reactions betweenacetylenes and cobalt carbonyl derivatives. The nature of most of theproducts is unknown; many can be broken down to give aromatic C, ringsystems. Some of the complexes are formulated as derivatives of cyclopen-tadienones and some have been regarded as containing a cyclobutadienelooE. 0. Fischer and K. Ulm, Chem.Ber., 1961, 94, 2413.lolD. Jones and G. Wilkinson, Chem. and Ind., 1961, 1408.lozR. Criegee and P. Ludwig, Chem. Ber., 1961, 94, 2038.Io3F. J. Impastato and K. G. Ihrman, J . Amer. Chem. SOC., 1961, 83, 3726.lo4 W. Strohmeier and D. von Hobe, 2. Naturforsch., 1961, 16b, 402.lo6M. Tsutsui and H. Zeiss, J . Amer. Chem. SOC., 1961, 83, 825; cf. Ann. Reports,lo6L. F. Dahl and D. L. Smit,h, J . Amer. Chem. Xoc., 1961, 83, 752.1959, 56, 142; 1960, 57, 148116 INORGANIC CHEMISTRYring system as a bridge between two cobalt atoms. Hg[Co(CO),], reactswith Me,C*CrCH to give the complex (13) in which the acetylenes havetrimerised in an unsymmetrical manner. On degradation this complex gives( R = CMe3)1,2,4-tri-t-butylbenzene.1°7 Dimethyl acetylenedicarboxylate acts as adienophile towards di-n-cyclopentadienylnickel(11) and gives 2-n- (2,3-bismeth-oxycarbonylnorborna-2,5-dien-7-yl)-n-cyclopentadienylnickel( rr) (14).l08To judge from this reaction and from the details of some of the structureswhich have been published this year, considerable work needs to be doneto establish the reasons why the double bonds in polyene complexes some-times behave as if they were independent and sometimes as if they wereconjugated.(g) Complexes with aromatic systems. 4-Bromo- lY2,3,4-tetraphenylbuta-cis-1 ,cis-3-dienyldimethyltin bromide (16) [prepared by the action of brominePh PhP h O P h BrMe2SnCPh = CPh-CPh=CPhBrMe Me 2"\ (IS) 0 6 )on 1 ,l-dimethy1-2,3,4,5-tetraphenylstannole (15)] reacts with nickel bromideto give n-tetraphenylcyclobutadienenickel dibromide.The uncomplexedcyclobutadiene system may have a triplet ground state and evidence for thisis found in the transitory green colour observed during the reaction and inthe great avidity of the unknown intermediate for oxygen.lo9 Detailedinfrared and Raman spectral studies of dicyclopent adienylmagnesium indi-cate that this should be considered as a true sandwich compound withconsiderable covalent character in the metal-ring bond. This immediatelybroadens the field of possible sandwich compounds to include many deriva-tives of non-transition metals. 110 Di-n-cyclopentadienyltitanium dichlorideis reduced by di-isobutylaluminium chloride to the deep-violet compound(n-C,H,)TiCl,. It is insoluble in all hydrocarbons but gives a blue solutionin acetonitrile; it is not a catalyst for the polymerisation of ethylene.ll1Mixed halogenoalkoxy-n-cyclopentadienyl derivatives of titanium( 1v) can belo' U.Kriierke, C. Hoogzand, and W. Hiibel, Chem. Ber., 1961,94,2817; U. Kriierkeand W. Hiibel, ibid., p. 2829.lo8M. Dubeck, J. Amer. Chem. SOC., 1960, 82, 6193.loeH. H. Freedman, J . Amer. Chem. Soc., 1961, 83, 2194, 2195.110 E. R. Lippincott, J. Xavier, and D. Steele, J . Amer. Chem. Soc., 1961, 83, 2262.lXIP. D. Bartlett and B. Seidel, J . Amer. Chenb. SOC., 1961, 83, 581SHARP: THE TRANSITION ELEMENTS 117obtained by the action of sodium cyclopentadienide on the titanium( IV)halogenoalkoxides.112 Niobium and tantalum pentahalides react withsodium cyclopentadienide to give violet compoundswhich are formulated (17) with two n-cyclopentadienylrings and two a-cyclopentadienyl rings.l13 A new cyclo-pentadienyl derivative, [ (C,H,),Tc],, has been synthesisedby the action of sodium cyclopentadienide on tech-netium tetrachloride. It is different in type from knownmanganese and rhenium derivatives and must probablybe formulated with a metal-metal bond as is presumedfor the carbonyl.114 Further n-cyclopentadienyl derivatives containingmetal-metal bonds linking two different elements have been synthesised,(~-C,H,)Mo(CO),Na and Mn(CO),Na react with (n-C,H,)Fe(CO),I to give(n-C,H,)Mo(CO),Fe(n-C,H,)( CO), and Mn( CO),Fe(n-C,H,) (CO),, respectively.Di-n-cyclopentadienylnickel reacts with iron pentacarbonyl to give(n-C,H,)Ni(CO~Fe(n-C,H,)(CO), in which there are almost certainly bridgingcarbonyl groups in addition to the metal-metal b0nd.1~5 Chloro-n-cyclo-pentadienyliron dicarbonyl gives cationic species [ (n-C,H,)Fe( CO),] + and[(n--C5H5)Fe(CO),(Ph3M)]+ (M = P, As, Sb) under the influence of carbonmonoxide or a Ph,M ligand.Reduction of the tricarbonyl species withsodium borohydride gives (n-C,H,)Fe(CO),H, but the triphenylphosphine-substituted cation gives dicarbonylcyclopentadienetriphenylphosphineiron-(0).116 Fulvenes and azulenes react with ferrous salts in the presence oflithium aluminium hydride to give substituted ferrocenes, and the samegeneral method can be used for the preparation of n-cyclopentadienyl deri-vatives of other elements.l17 Solvolysis studies on ferrocenyl-, rutheno-cenyl-, and osmocenyl-methyl acetates indicate a high stability for theresulting intermediate carbonium ions and there is a strong possibility ofdirect bonding between the metal atom and the cationic carbon.118 Eachmember of the series (n-C,H,),Fe, (n-C,H,),Ru, and (n-C,H,),Os is oxidisedin a different manner. Ferrocene is oxidised by a one-step one-electronoxidation, ruthenocene by a two-step one-electron oxidation, and osmoceneby a one-step two-electron oxidation.As is to be expected, the actualoxidation potentials depend upon the electron-withdrawing power of thesubstituents in the ring systems. 119 n-Cyclopentadienylrhodium dicarbonylhas been prepared by the action of sodium cyclopentadienide on[Rh(CO),Cl],.120The n-arene-transition metal complexes have been reviewed. 121 InA. N. Nesmeyanov, 0. V. Nogina, and A. M. Berlin, Dolclady Akad. NaukS.S.S.R.,QPpyMw( ' 7 )1960, 134, 607.ll3E. 0. Fischer and A. Treiber, Chem,. Ber., 1961, 94, 2193.114D. K. Huggins and H. D. Kaesz, J . Amer. Chew&. SOC., 1961, 83, 4471.115 R. B. King, P. M. Treichel, and F. G. A. Stone, Ghem and Ind., 1961, 747;116 A. Davison, M. L. H. Green, and G. Wilkinson, J . , 1961, 3172.11' G. R. Knox and P. L. Pauson, J . , 1961, 4610; G. R. Icnox, J. D. Munro, P. L.l18E. A. Hill and J. H. Richards, J . Amer. Chem. Soc., 1961, 83, 3840, 4216.llD T. Kuwana, D. E. Bublitz, and G. Hoh, J . Amer. Chem. SOC., 1960, 82, 5811.120E.0. Fischer and K. Bittler, 2. Naturforsch., 1961, 16b, 225.121 E. 0. Fischer and H. P. Fritz, Angew. Chern., 1961, 73, 353.J. F. Tilney-Bassett, Proc. Chena. SOC., 1960, 419; cf. Ann. Reports, 1960, 57, 149.Pauson, G. H. Smith, and W. E. Watts, J., 1961, 4619118 I N O R G A N I C CHEMISTRYspite of the structure which shows alternate short and long C-C bonds inthe rings, di-n-benzenechromium still retains considerable aromatic character,as is shown by its dimetallation by pentylsodium.122 Biphenylene formscomplexes with two and one molybdenum tricarbonyl residues; in bothcases the metal is bonded to the six-membered ring systems and not to thefour-membered ring.123 The di-n-benzenetechnetium(1) cation has beenobtained by irradiation of di-n-benzenemolybdenum with neutrons :n, YMo(C6H6)2 4 [Tc(C6H6),lf;it can be isolated as the insoluble tetra~heny1borate.l~~ Triphenylmethylfluoroborate will abstract hydride ion from z-cyclopentadienylcyclohexa-dienecobalt(1) to give the [ (~-C,H,)(~-C,H,)CO]~+ cation.125 A series ofcomplexes in which different functional groups in an organic molecule areco-ordinated to different metal atoms have been prepared.Thus 1,4-diphenylbutadiene gives mono- and di-chromium tricarbonyl derivatives andP h O - Phthese react further with iron pentacarbonyl to give the complexes (18) and(19). The possibilities of this type of reaction appear almost endless andvariations can be effected by use of olefin, acetylene, cyclopentadienyl, andaryl derivatives.126 A solution of sodium hexacarbonylvanadate( -I) indiethylene glycol dimethyl ether reacts with cycloheptatriene to give thegreen diamagnetic compound n-cycloheptatrienylvanadium tricarbonyl.Tropylium bromide will not give this derivative dire~t1y.l~~Organometallic Compounds of the Transition Elements.-The mostnotable feature of this section of inorganic chemistry has been the rapiddevelopments in the knowledge of the fluoroalkyl derivatives of the transi-tion elements.It is now clear that these compounds are much more stablethan the corresponding hydrocarbon compounds. Metal hydrides will addacross the double bond of a perfluoro-olefin to give compounds of the typeHCF,*CF,*Mn(C0)5 and HCF,*CP,*MO(CO),(~-C,H,).~~~ Perfluoroacyl de-rivatives of the groupings Mo(CO),(n-C,H,), Mn( CO),, and )Co(CO), resultfrom the action of the acyl chloride or anhydride on an appropriate alkali-metal salt; they lose carbon monoxide when heated and are convertedinto the corresponding perfluoroalkyl derivatives.The reaction betweentrifluoroiodomethane and sodium pentacarbonylmanganate( -I) givesMn(Co)51,97, 129 but perfluoroalkyl derivatives of iron and cobalt can be122E. 0. Fischer and H. Brunner, 2. Naturforsch., 1961, 16b, 406.123 J. Chatt, R. G. Guy, and H. R. Watson, J., 1961, 2332.124 F. Baumgartner, E. 0. Fischer, and U. Zahn, Chem. Ber., 1961, 94, 2198.125E. 0. Fischer and R. D. Fischer, 2. Naturforsch., 1961, IGb, 556.126M. Cais and M. Feldkimel, Tetrahedron Letters, 1961, 440, 444; J.F. Tilney-Bassett, J., 1961, 577; T. A. Manuel, S. L. Stafford, and F. G. A. Stone, J . Amer. Chew.Soc., 1961, 83, 3597.I27R. P. M. Werner and S. A. Manastyrskyj, J . Amer. G'hem. SOC., 1961, 83, 2023.128R. B. King, P. M. Treichel, and F. G. A. Stone, Proc. Chem. SOC., 1961, 69.129T. H. Coffield, J. Kozikowslri, and R. D. Closson, Vth Internat. Conf, Co-ordSHARP: THE TRANSITION ELEMENTS 119prepared by the action of trifluoroiodomethane and its higher homologues.Iron pentacarbonyl gives compounds RpFe(CO),I and [R,Pe(CO),I], andn-cyclopentadienylcobalt dicarbonyl gives (n-C5H,)Co(CO)RFI.* The brownsolutions that result from the action of sodium on a solution of tri-irondodecacarbonyl in tetrahydrofuran react with perfluoroacyl chlorides to givederivatives (R,),Fe(CO),, similar to the heterocyclic compound describedlast year.A similar compound (C,F,),Co(CO)(n-C,H5) results from theact ion of tetra fluoroet h ylene on TC - c y clo pent adien y lco balt dicarb on yl .97 5 130Further evidence that the first step in hydroformylation and in olefin-isomerisations that are catalysed by cobalt carbonyl hydride is the additionof the hydride across the double bond of the olefin, has come from isolationof the actual intermediate organometallic compounds as their triphenyl-phosphine adducts. A unified mechanism has now been advanced for bothof these reacti0ns.1~1 Metal ions can interact with organic free radicals togive organometallic derivatives which may ultimately break down to thedimer of the radical.An aqueous solution of phenyl t-butyl hydroperoxidereacts with chromous sulphate to give the [Ph*CH,Craq.I2 + cation identicalwith that prepared by the action of benzyl chloride on chromous perchlor-ate. The carbonylation of organometallic derivatives has been extendedto the trans-[MXR(PEt,),] complexes (M = Pd, Pt; R = alkyl or aryl).The palladium derivative gives an acyl compound at atmospheric pressure ;higher pressures must be used for the platinum compound. The carbonylcompounds that are presumably present as intermediates have not beeni~olated.13~ 2,2’-Bipyridyl (bipy) and dimeric acetylacetonatotrimethyl-platinum react to give the compound Me,Pt(Me*CO-CH*CO*Me)(bipy) inwhich the platinum atom is in octahedral co-ordina-atoms of the bipyridyl, and the active methylene MeC\H,CMe Ccarbon of the p-diketone (20).The carbonyl oxygen Me= I -,.pieatoms are not co-ordinated to the metal and the “P t -.Cyclo-octatetraeneplatinum(11) iodide reacts withpounds R,Pt(C&,)PtR, in which the two platinumatoms are bridged by the cyclic olefin.and other strongly n-bonding ligands.l35tion from three methyl groups, the two nitrogen 0 9. ,diketone is acting as a monodentate ligz~nd.13~ /Me‘\Grignard reagents to give the organometallic com- - I (20)The olefin is displaced by phosphinesChem., London, 1959, The Chemical Society, London, 1960, p. 126; H. D. Kaesz,R. B. King, and F. G. A. Stone, 2. Naturforsch., 1960, 15b, 763; W. Hieber, W. Beck,and E. Lindner, ibid., 1961, 16b, 229; W.R. McClellan, J . Amer. C h m . SOC., 1961, 83,1598; W. Beck, W. Hieber, and H. Tengler, Chem. Ber., 1961, 94, 862.l30 T. D. Coyle, R. B. King, E. Pitcher, S. L. Stafford, P. M. Treichel, and F. G. A.Stone, J . Inorg. Nuclear Chem., 1961, 20, 172; R. B. King, P. M. Treichel, and F. G. A.Stone, J . Amer. Chem. SOC., 1961, 83, 3593; cf. Ann. Reports, 1960, 57, 150.131 R. F. Heck and D. S. Breslow, J . Amer. Chem. SOC., 1961, 83, 4023.132 J. K. Kochi and F. F. Rust, J . Amer. Chem. SOC., 1961,83,2017; cf. F. A. L. Anetand E. Leblanc, ibid., 1957, 79, 2649.133G. Booth and J. Chatt, Proc. Chem. SOC., 1961, 67.134A. G. Swallow and M. R. Truter, Proc. Chenz. SOC., 1961, 166.135 J. R. Doyle, J. H. Hutchinson, N. C. Baenziger, and L. W.Tresselt, J . Amer.Chem. SOC., 1961, 83, 2768.* Rp = perfluoroalkyl120 INORGANIC CHEMISTRYMolecular Hydrides of the Transition Elements.-A study of the visibleand ultraviolet spectra of the complexes trans-[RuXY (C,H,(PMe,),f ,](X = Y = C1, Br, I, CN; X = H, Me, Ph, p-Me*C6H4, Y = C1) has shownthat the hydride and organometallic radicals have large ligand-field strengthsbut that these field strengths are less than that of the cyanide i0n.136ReX,(PR,), derivatives are reduced by sodium borohydride in ethanol toReH,( PR,),(Et*OH),. The solvating ethanol is lost on crystallisation frombenzene, and the hydride will then react with more triphenylphosphine togive ReH,(PR,),, an air-stable hydride which is converted into the paramag-netic complexes ReX,(PR,), by HX (X = C1, Br).137 Various papers havegiven further information on the products (hydrides, carbonyls, carbonylhydrides, or complexes of the Group V ligands) from the reactions of transi-tion-metal halides with alcohols in the presence of suitable ligands.Thereactions are generally carried out in the presence of a base but this appearsto be unnecessary when the process takes place at 100" or above. Inaddition to the complexes reported previously, new derivatives of the types,IrX(CO)L,, and II-H~X(,-~)L, (n = 1 or 2; X = C1 or Br; L = PPh,,AsPh,, or SbPh,) have now been is01ated.l~~ When sodium borohydrideis used to reduce transition-metal halide derivatives the products are gener-ally metal hydrides rather than salts of the metal in lower oxidation states.trans-Bisethylenediaminedichlororhodium(1II) chloride gives a pale brownsolution containing the [Rh1Ien2HC1] + cation.The other ligands in thisgrouping are not generally recognised as giving rise to strong n bondingand n bonding does not appear to be necessary to confer stability on transi-tion-metal hydrides. 139 Iridium tribromide and triphenylphosphine reactwith sodium borohydride to give two products of the formula IrH,L,,which can also be obtained more indirectly by the action of lithium alumi-nium hydride on IrHCl,L, in tetrahydrofuran. They are presumablystereoisomers, and they give IrH,L,X (X = acetate, hydrogen oxalate, hydro-gen malonate, or hydrogen tartrate) with acids and react with perchloric acidto give IrH,L,C10,, a compound which probably contains an [IrH,L,]+cation.140 Potassium t e trac hloro pla tinate ( II) reacts with trip hen y 1 p hosp hinein the presence of ethanol and potassium hydroxide to give compoundswhich are now recognised as hydrides PtH,L,, PtH,L,, and PtH,L,;the same products result from the reduction of bistriphenylphosphineplati-num(n) iodide in ethanol.(R = Ph, Me), prepared by reduction of the corresponding chlorides withsodium borohydride or sodium naphthenide, are true compounds of zero-positive platinum.141[RuC12(CO)2(PR3)]2~ RuBr3(C0)(PR3)2, [RuC12(Co)(AsR3)]3~ IrH2C1(PR,)3,However, the complexes Pt( R,P*CH,*CH,-PR,)136 J. Chatt and R. G. Hayter, J., 1961, 772.137M. Freni and V. Valenti, Gazzetta, 1961, 91, 1357.138 J.Chatt and B. L. Shaw, Chem. and Id., 1961, 290; L. Vaska, ibid., p. 1402;J . Amer. Chem. SOC., 1961, 83, 756; L. Vaska and J. W. DiLuzio, ibid., pp. 1262, 2784;cf. Ann. Reports, 1960, 57, 152.139 G . Wilkinson, Proc. Chem. SOC., 1961, 72.140 L. Malatesta, M. Angoletta, A. ArAneo, and F. Canziani, Angew. Chem., 1961,73, 273; R. G. Hayter, J . Amer. Chem. SOC., 1961, 83, 1259.141 J. A. Chopoorian, J. Lewis, and R. S. Nyholm, Nature, 1961, 190, 529; J. Chattand G. A. Rowe, ibid., 1961, 191, 1191; cf. L. Malatesta and C. Cariello, J., 1958, 2323SHA4RP: THE TRANSITION ELEMEPU’TS 121Scandium, Yttrium, and the Rare Earths.-A new book has been pub-lished on the chemistry of yttrium and scandium,14z and the chemistries ofthe rare-earth and actinide sulphides have been reviewed.143 The hydroxidesof the heavier lanthanides are amphoteric, and salts Na,M(OH), (M = Yb, Lu)can be prepared by the action of concentrated sodium hydroxide on thehydroxides in an a~toclave.14~ High-temperature fluorination of mixturesof sodium chloride and praseodymium chloride gives NaPrF, in additionto the previously known Na,PrF6.145 GdCl,,GH,O contains [Cl,Gd( OH,),] +eight-co-ordinate cations which have a completely unsymmetrical configura-tion. The actual structure appears to be a common one amongst the rare-earth and actinide halide h e ~ a h y d r a t e s .~ ~ ~ More chlorodiborohydrides,MC1(BH4), (M = Gd, Tb, Dy, Er, and Tb), have been prepared by the reac-tion between the appropriate metal trichloride and lithium borohydride intetrahydrofuran. The action of heat on the gadolinium and terbium corn-pounds gives MC1( B,H,) derivatives whilst the samarium wmpound givesSm,C1,( B,H6). It is possible that these compounds contain (B,H,) - ions.147The reduction of lanthanide halides with lanthanide metals continues to bestudied. Neodymium trichloride gives various products ; neodymium di-chloride has the samarium dichloride structure and Nd11.95 is isomorphouswith samarium dibromide so that it appears definite that these compoundscontain dipositive neodymium. Lanthanum, cerium, and praseodymiumdi-iodides have been prepared; they are all isostructural and have a metallicappearance with a high conductivity in the solid state. It is suggested thatthey should be formulated M3+e-(I-),.148The Actinides.-The fluorides of the actinide elements have beenreviewed.149 Reduction of a solution of tripositive actinium in citric acidgives an amalgam; by analogy with the properties of the rare-earth ele-ments, this is considered as evidence for the existence of a dipositive oxida-tion state for this element.150 The system caesium fluoride-thorium tetra-fluoride is as complex as the similar systems involving other alkali-metalfluorides, and phases in which the components have ratios of 3 : 1, 2 : 1,1 : 1, 2 : 3, 1 : 2, 1 : 3, and 1 : 6 are formed;151 alkali chlorides react withthorium tetrachloride to give the phases MThCl,, M,ThCl,, and M,ThCl,(applicable to all M except for Na3ThC1,).152 The chemistry of prot-actinium has been reviewed.lS3 An electrometric study has been made142 R.C. Vickery, “ The Chemistry of Yttrium and Scandium,” Pergamon, London,143 G. V. Samsonov and S. V. Razikovskaya, Uspelchi Iihim., 1961, 60 [ZS].144 B. N. Ivanov-Emin and L. A. Nisel’son, Zhur. neorg. Khim., 19C0, 5, 1921 [937].la5L. B. Asprey and T. K. Keenan, J. Inorg. Nuclear Chem., 1961, 16, 260; cf.R. Hoppe, Angew. Chern., 1959, 71, 457.146 M. Marezio, H. A. Plettinger, and W. H. Zachariasen, Acta Cryst., 1961, 14, 234.14’ K. Rossmanith and E. Muckenhuber, Monatsh., 1961, 92, 600; K. Rossmanith,&id., p. 768; cf. A. Brukl and K. Rossmanith, ibid., 1959, 90, 481.14* L. F. Druding and J. D. Corbett, J. Amer. Chem. SOC., 1961, 83, 2462; J.D. Cor-bett, L. F. Druding, and C. B. Lindahl, J. Inorg. Nuclear Chem., 1961, 17, 176.laON. Hodge, Adv. Fluorine Chem., 1961, 2, 138.150 G. BouissiAres, M. Haissinsky, and Y. Legoux, Bull. SOC. chim. France, 1961, 1028.I5lR. E. Thoma and T. S. Carlton, J . Inorg. Nuclear Chem., 1961, 1’7, 88.152 V. I. Ionov, B. G. Kovshunov, V. V. Kokorev, and I. S. Morozcv, Izwest. Vysshikh153V. A. Mikhailov, Uspekhi Khim., 1960, 882 14191.1960.Ucheb. Zavedenii, Tsvetnaya Met., 1960, 3, 102122 IN 0 RG AN I C CHEMISTRYof the hydrolysis of the uranyl ion and it has been shown that in sodiumsulphate solution sulphato-groups are closely associated with the condenseduranyl residues ; core-link complexes of the type {UO,[ ( 0H),UO,ln j 2 + arefound in s01ution.l~~ Oxygen exchange between water and the uranyl ionis catalysed by the UO,+ ion which undergoes exchange with both activatedwater and the uranyl ion;155 the oxygen liberated during the decompositionof U04,2H,0 originates in the metal peroxide which is thus established asa true peroxide; a new uranium peroxide hydrate, U0,,4H20, has beenfound in this system.156 Previous attempts to prepare uranium(1v) nitratein aqueous and non-aqueous solvents have given oxy-species but it hasnow been found that salts UX,,nCH,*CO-NMe, (X = C1, NO,) can be pre-pared in dimethylacetamide and that addition of an ionic nitrate to a ura-nium(1v) solution in a mixture of nitric acid and sulphamic acid gives com-plex salts M,U(NO,), (M = Cs, Et4N).l5' A series of new uranium selenides,Use,, U3Se5, U,Se,, U,Se4, have been prepared by the action of hydrogenand selenium on uranium tetrachloride; UO, and UTe, interact to give anoxytelluride, UOTe.158 Although all previous work has indicated that thecompound formed by uranium hexafluoride and sodium fluoride is 3NaF,UF,,fluorine-exchange studies are in favour of 2NaF,UF6 as the stable adduct.159Plutonium trifluoride gives a 1 : 1 adduct with sodium fluoride but thereis no compound formation in the system LiF-PuF3;160 rubidium chloridegives 1 : 2, 2 : 1, and 3 : 1 adducts with plutonium trichloride, czesiumchloride gives 1 : 2 and 3 : 1 adducts.161 Americium(m) hydroxide isoxidised by hypochlorite to the tetrapositive hydroxide which will reactwith aqueous ammonium fluoride to give a pink-red solution of an ameri-cium(rv) complex fluoride. This is the first observation of an americium(rv)compound in solution; on acidification there is disproportionation to anamericium(m) and an americium(v) or americium(vr) species.162 Ascurium(1v) fluoride oxidises the ammonium ion, ammonium fluoride cannotbe used to prepare a curium(1v) solution but curium tetrafluoride will dissolvein a solution of czesium fluoride to give a fairly stable curium(1v) s01ution.l~~Titanium, Zirconium, and Ha€nium.-The organic chemistry of titaniumhas been reviewed with particular reference to alkoxides and the organo-metallic intermediates used as Ziegler-type catalysts. l G 4 Potassiumcyanide reacts with titanium tribromide or hexa-amminetitanium(II1)154A. Peterson, Acta Chem.Xcand., 1961, 15, 101.155G. Gordon and H. Taube, J. Inorg. Nuclear Chem., 1961, 16, 272.156 G. Gordon and H. Taube, J. Inorg. Nuclear Chem., 1961, 16, 268; L. Silvermanand R. A. Sallach, J. Phys. Chem., 1961, 65, 370; T. Sato, Naturwiss., 1961, 48, 668.157K. W. Bagnall, P. 8. Robinson, and M. A. A. Stewart, J., 1961, 4060.158 P. Khodadad, Bull. SOC. chirn. France, 1961, 133; W. Trzebiatowski, J. Niemier,and A. Sepichowska, Bul. Acad. polon. Sci., Ser. Sci. chim., 1961, 9, 373.159 I. Sheft, H. H. Hyman, R. M. Adams, and J. J. Katz, J. Amer. Chem. Xoc., 1961,83, 91.160 C. J. Barton, J. D. Redman, and R. A. Strehlow, J. Inorg. Nuclear Chem., 1961,20, 45; C. J. Barton and R. A. Strehlow, ibid., 1961, 18, 143.161R. Benz and R.M. Douglass, J. Phys. Chern., 1961, 65, 1461.16zR. A. Penneman, J. S. Coleman, and T. K. Keenan, J. Inorg. Nuclear Chem.,1961, 17, 138; L. B. Asprey and R. A. Penneman, J. Amer. Chem. SOC., 1961, 83,2200.163 T. K. Keenan, J. Anaer. Chem. SOC., 1961, 83, 3719.1641. Shiihara, W. T. Schwartz, jun., and H. W. Post, Chem. Rev., 1961, 631, 1SHARP: THE TRANSITION ELEMENTS 123bromide to give a complex K,Ti(cN),,BKCN; this appears to be the fistknown complex cyanide of t i t a n i u m ( ~ ~ ~ ) . ~ ~ ~ Complexes MCl,,D (M = Ti)and MCI4,2D (M = Ti, Zr, Hf, V) are formed by reaction between o-phenyl-enebisdimethylarsine and Group IV tetrahalides. TiCl,,BD contains an eight-co-ordinated titanium atom, the co-ordination arrangement being similarto that found for the [Mo(CN),]4- ion in the solid state; it is the first exampleof an eight-co-ordinate metal atom in the first transition series althoughseven-co-ordinate manganese and iron species have been reported this year(pp. 127, 128) and have previously been assumed as intermediates in reac-tions.166 By contrast, titanium(1v) has been shown to have tetrahedralco-ordination by oxygen in the titanium garnets M,TiO, (M = Sr, Ba).167Various mixed-metal oxides containing titanium in oxidation states lowerthan four have now been described.Hydrogen reduces Na2Ti,07 a t 950"to a blue-black titanium oxide bronze Na,TiO, (x -0.2)) and the potassiumsalt can be prepared similarly. Titanium and manganese dioxides reactat 1400" to give the black spinel Mn11Ti11120,.168 An oxychloride, TiOCl,,results from the action of chlorine monoxide on titanium tetrachloride ; itgives adducts TiOC12,2L with pyridine and with phosphorus oxychloride,and complex chlorides M2TiOC14,H,0 (M = Cs, Rb) derived from it canbe isolated from solutions of titanium dioxide in hydrochloric a~id.16~ Thecompounds MTiIJC1,, M2TiI1C1, (M = Rb, Cs), M,TilIICI, (M = Na, K, Rb),and MTi111C14 (M = Rb, Cs) have been identified in the various systemsbetween alkali-metal chlorides and titanium chlorides.17* Potassium chlor-ide, titanium tetrachloride, and phosphorus oxychloride react to give thecompound KTiCl,,POCl, which is an electrolyte in suitable solvents andappears to contain the [TiCl,,OPCl,]- anion.171 Titanium and zirconiumtetrachlorides give monomeric acetylacetonates, TiCl,(acac), and ZrCl( acac),(Hacac = acetylacetone) by direct reaction with acetylacetone.172 Ammo-nolysis of hexachloro- and hexabromo-titanates( ~ v ) proceeds in a similarmanner to that of the tetrahalides, two Ti-X bonds generally being broken;in the ammonolysis of hexachlorozirconates(rv) only one Zr-C1 bond isbroken.The products are mixtures but portions are generally soluble inliquid ammonia, presumably because of the formation of amido-species asani01-1.s.l~~ Titanium dibromide, with the cadmium iodide structure, canbe prepared by reduction of the tetrabromide by metallic titanium.174The tetraoxalatozirconium( IV) anion has a dodecahedra1 configuration about165H.L. Schliifer and R. Gotz, 2. anorg. Chem., 1961, 309, 104.166 R. J. H. Clark, J. Lewis, R. S. Nyholm, P. J. Pauling, and G. B. Robinson,167 J. A. Bland, Acta Cry8t., 1961, 14, 875; P. Tarte, Nature, 1961, 191, 1002.lssA. D. Wadsley and S. Andersson, Nature, 1961, 192, 551; A. Lecerf and A.169 K. Dehnicke, 2. unorg. Chern., 1961,309,266; I. S. Morozov and G. M. Toptygina,l T O P. Ehrlich and R. Schmitt, 2. u w g . Chem., 1961, 308, 91; B. F. Markov andI7lV. Gutmann and F. hlairinger, Monatsh., 1961, 92, 720.172D. M. Puri and R. C. Mehrotra, J. Less Common Metals, 1961, 3, 247.lT3 G. W. A. Fowles and D. Nicholls, J., 1961,95; J. E. Drake and G. W. A. Fowles,J . Inorg. Nuclear Chem., 1961, 18, 136; J . Less Common Metals, 1961, 3, 149.174P.Ehrlich, W. Gutsche, and H.-J. Seifert, 2. anorg. Chem., 1961, 312, 80.Nature, 1961, 192, 222.Hardy, Compt. rend., 1961, 252, 131.Zhur. neorg. Khim., 1960, 5, 2518 [1218].R. V. Charnov, Ukrain. khim. Zhur., 1961, 27, 34124 INORGANIC CHEMISTRYthe metal atom, a configuration which is as probable as the square anti-prism for eight-co-ordinated species.17, A detailed study has been madeof the hydrolysis products of zirconium tetrafluoride and some fluorozir-conates(1v) but the products are complex and their full structures are not yetknown. Acid hydrolysis of fluorozirconates gives compounds of the typeK1.5H0.5Zr2F80, and in alkaline solution KZrF,( H,O) is hydrolysed toKZrF,O by way of KZrF,(OH), whilst NH,ZrF,(H,O) goes to Zr4Fl,03.ZrF4,H,0 is hydrolysed to ZrF3( OH),H,O and ZrF2( OH),,H,O ; when heatedthe hydroxy-fluorides are converted into polymeric oxyfluorides. 176Vanadium, Niobium, and Tantalum.-Zero-positive complexes ML,(M = V, Cr, W) of the disphosphine Me,P*CH,*CH,*PMe, can be preparedby reduction of the metal halides in tetrahydrofuran in the presence ofthe diphosphine with lithium aluminium hydride or sodium naphthenide.The complexes are unstable with respect to oxidation; the vanadiumcompound is paramagneti~.~'~ The stable phases in the vanadium pent-oxide-lithium oxide system have ratios of the two constituents of 3 : 1, 1 : 1,and 1 : 3.178 Five-co-ordinated vanadium is found in bisacetylacetonato-oxovanadium (IV) ; the vanadium atom is near the centre of gravity of a squarepyramid of oxygen atoms from the two acetylacetonate groupings and thevanadyl oxygen.179 The reactions between vanadium and niobium penta-fluorides and some nitrogen bases have been studied. Vanadium penta-fluoride yields NH,VF, ,pyVF,, and en3VF4 ; niobium pentafluoride gives(NH,),NbF, and en,.$TbF,. The structures of these compounds and thephysical significance of their stoicheiometries are unknown. 180 Electro-lytic reduction of a vanadium(v) salt in hydrofluoric acid gives VF2,4H,O; aseries of acid salts VF,,xHF,GH,O (x = 1 to 5 ) are also forrned.l8l Vana-dium trichloride and trioxide interact in a sealed tube to give the reddish-brown oxychloride, VOCl. 182 Tripositive vanadium can be stabilised intetrahedral co-ordination in a caesium tetrachloroaluminate lattice ; thetetrahalogenovanadate(rr1) ions are deep blue ;lS3 salts of these anions canbe prepared by interaction of tetraethylammonium halides with vana-dium(m) halides in acetonitrile followed by removal of the acetonitrile ofsolvation at Vanadium trihalides are solvolysed by liquid ammonia;the primary product from the trichloride is VCl,(NH,),4NH3 which breaksdown when heated to give V(NH)Cl and then to VN.Vanadium dichloridegives ammines on reaction with ammonia at room temperature but ammono-lysis occurs a t higher temperat~res.1~~ A structural study of niobiumdioxide shows that it is built up from NbO, octahedra sharing edges andcorners. In agreement with the low magnetic susceptibility the niobium1 7 5 J.L. Hoard, G;. L. Glen, and J. V. Silverton, 3. Amer. Chenz. SOC., 1961,83, 4293.1'6L. Kolditz and A. Feltz, 2. anorg. Chern., 1961, 310, 204, 217.1 7 7 J. Chatt and H. R. Watson, Nature, 1961, 189, 1003.178R. Kohlmuller and J. Martin, Bull. Xoc. chim. France, 1961, 748.lT9R. P. Dodge, D. H. Templeton, and A. Zalkin, J. Chem. Phys., 1961, 35, 55.ISOR. G. Cave11 and H. C. Clark, J . Inorg. Nuclear Chem., 1961, 17, 257.lslH.-J. Seifert and B. Gerstenberg, Angew. Chem., 1961, 73, 657.l82D. M. Gruen and R. Gut, Nature, 1961, 190, 713.la3D, E. Scaife, Vth Internat. Cod. Co-ord. Chem., London, 1959, The Chemical1 8 4 G. W. A. Fowles, P. G. Lanigan, and D. Nicholls, Chenz. and Ind., 1961, 1167;Society, London, 1960, p. 152.H. Remy and I.May, Naturwiss., 1961, 48, 524SHARP: THE TRANSITION ELEMENTS 125atoms are moved towards each other in pairs joined by a metal-metalbond.185 The system Cs,0-Nb,06 contains phases with the oxides in theratios 5 : 13, 2 : 15, 1 : 2, 2 : 3, and 1 : 1.18s Fluorination of NbCI,,PCI,with arsenic trifluoride gives [NbClJB, an ionic substance which meltst o the covalent form NbC1,F. This type of behaviour is well knownwith halides of the phosphorus group but does not appear to have beenpreviously recognised in the transition series. Arsenic trichloride reactswith NbCl,,PCI, to give N~C~,,PCI,,ASCI,.~~~ The system of niobium oxy-chlorides has received considerable attention and it has now been establishedthat NbOCI, (two forms), NbO,Cl, and Nb,O,CI are all stable phases.Theoxytrichloride can be reduced with hydrogen or niobium to the oxydichloridewhich reacts with pentachloride to give the oxytrichloride and niobium tetra-chloride. A similar tantalum oxychloride, TaOCl,, is formed by heatingsilica or tantalum pentoxide and tantalum pentachloride. 188 Niobiummetal will reduce niobium pentabromide to the t'etra- and tri-bromide.Both of these can be transported in a temperature gradient; the tribromidehas a wide range of homogeneity, the lower limit being Nb,Br8.ls9Chromium, Molybdenum, and Tungsten.-The reaction between lithiumnitride and metals or metal nitrides at high temperatures under an atmo-sphere of nitrogen gives double nitrides Li,MN, (M = Cry Mo, W). Thechromium compound is miscible with lithium oxide and probably has anantifluorite structure.lgO Solutions of chromous salts in the presence ofpolyamines liberate hydrogen from homogeneous solution by an autocataly-tic reaction which gives polyamine complexes of chromium(m) as the otherproduct.191 Very closely allied to this are the observations that chro-mium(@ complexes of salicylic acid, 5-sulphosalicylic acid, or ethylene-diaminetetra-acetic acid are some of the most powerful reducing agentsknown in aqueous solution.The anodic half-wave potential for theCr2 f-Cr3 +-ethylenediaminetetra-acetic acid complex at pH 12 is + 1.48 v.192Chromium sesquioxide reacts with chromium monocarbide to give thecubic monoxide but the action of hydrogen on a mixture of the sesquioxideand Cr3C, gives a new carbide, Cr2C.lg3 The reaction between dichromatesand anhydrous alcohols gives solutions containing [ROCrO,] - anions ; theultraviolet spectra of these solutions are in complete accord with the loss oftetrahedral symmetry in going from a chromate to an alkoxychromate(vI)grouping.lg4 A survey of the older literature has shown many compoundsthat may be heteropolychromates ; iodates react with chromium trioxide togive salts MCrIO, and the ammonium salt has been shown to contain atetrahedral chromate ion which shares one oxygen atom with a trigonallS5 B.-0.Marinder, Acta Chem. Scund., 1961, 15, 707.lssA. Reisman and J. Mineo, J . Phys. Chem., 1961, 85, 996.lS7L. Kolditz and G. Furcht, 2. anorg. Chem., 1961, 312, 11.lS8 H.Schafer, E. Sibbing, and R. Gerken, 2. anorg. Chem., 1961,307,163; K. HubrlseH. Schafer and K.-D. Dohmann, 2. anorg. Chem., 1961, 311, 134.IsoR. Juza and J. Hary, 2. anorg. Chem., 1961, 309, 276.lslK. D. Kopple, G. F. Svatos, and H. Taube, Nature, 1961, 189, 393.lS2R. L. Pecsok and W. P. Schaefer, J . Arne?. C'hem. SOC., 1961, 83, 62.IS3H. Lux and L. Eberle, Chem. Ber., 1961, 94, 1562.lg4U. KlBning and M. C. R. Symons, J., 1961, 3204.and I. Baunok, Chimia, 1961, 15, 365126 INORGANIC CHEMISTRYiodate ion. lg5 2,2’-Bipyridyl and o-phenanthroline complexes are generallyprepared by reaction between the ligand and a metal compound in a lowoxidation state, but it has now been found that direct reaction between theligands and hexa-aquochromium(m) ions yields diaminodihydroxy-complexeswith no formation of the triamino-derivatives.Two forms of these diaminecomplexes are known; what is probably the trans-form comes out of solutionwhilst the cis-form remains in.lS6 Chromyl azide has been prepared bydirect reaction between chromium trioxide and hydrazoic acid in an inerts01vent.l~~ The structure of chromium(I1) chloride shows octahedra ofchlorine atoms about each chromium atom; as is usual with chromium(n)compounds the octahedron is distorted to contain two long and four shortCr-CI bonds.198 Chromium(m) chloride and oxide react to give CrOCl;this oxychloride is decomposed by heat.lg9 Two new borides, MoB,and WB,,have been prepared by interaction of the elements a t 1100°.200 Infraredstudies of the complex molybdenum(m) thiocyanates indicate that these areisothiocyanates with nitrogen bonded to the metal; the water of crystalli-sation in these compounds is not bonded to the metal. From magneticstudies it is inferred that K,Mo( CN) ,,2H,O contains seven-co-ordinatemolybdenum.201 Mo~S, has been found to have a structure very similarto that of niobium dioxide; the co-ordination about the metal is octahedralbut pairs of molybdenum atoms are joined by a metal-metal bond.202The solvolysis of molybdenum halides has received much attention.Thepentachloride gives adducts with tertiary amines but aminolysis occurswith primary and secondary amines to give products of the typesMoCl,(NRR’), and MoCl,(NRR’), (R, R‘ = alkyl or H).,03 Solvolysisoccurs with methanol to give MoCl,( OMe), , MoCl,( OMe),,SMeOK, andMoOC1,,2MeOH which react with pyridinium chloride to give[pyH][MoCl,( OMe),] or [pyH][MoOCl,].Mo02C12 and W02C12 with alcoholsgive alkoxides Mo,(OR), but Mo02C1, gives a series of complexes withacid anhydrides, esters, ethers, ketones, aldehydes, and nitriles in whichthere has been no breaking of the Mo-C1 b0nd.20~ It is only just becomingapparent how extremely reactive molybdenum pentachloride is, and it hasbeen found t o be dissociated into MoCl, and chlorine even in carbon tetra-chloride solution.205 Hexagonal tungsten nitride has been identified asW2N. The co-ordination about the nitrogen atoms is octahedral but theco-ordination sphere about the tungsten consists of a pyramid of three nitro-195K.-A.Wilhelmi and P. Lofgren, Acta Chem. Scad., 1961, 15, 1413.196R. G. Inskeep and J. Bjerrum, Acta Chem. Scand., 1961, 15, 62.197H.-L. Krauss and F. Schwarzbach, Chem. Ber., 1961, 94, 1205.198 J. W. Tracy, N. W. Gregory, E. C. Lingafelter, J. D. Dunitz, H.-C. Mez, R. E.Rundle, C. Scheringer, H. L. Yakel, jun., and M. K. Wilkinson, Acta Cryst., 1961, 14,927; cf. H. R. Oswald, Helv. Chim. Acta, 1961, 44, 1049.199H. Schafer and F. Wartenpfuhl, 2. anorg. Chem., 1961, 308, 282.2 o o A . Chretien and J. Helgorsky, Compt. rend., 1961, 252, 742.201 J. Lewis, R. S. Nyholm, and P. W. Smith, J., 1961, 4590.202 F. Jellinek, hTature, 1961, 192, 1065.203D. A. Edwards and G. W. A. Fowles, J., 1961, 24.204 H. Funk, F.Schmeil, and H. Scholz, 2. anorg. Chem., 1961, 310,86; H. Funk, E.Ebert, and F. M o w , 2. Chem., 1961, 1,190; H.-L. Krauss and W. Huber, Chem. Bey.,1961,94, 2864; cf. D. C. Bradley, R. K. Multani, and W. Wardlaw, J., 1958, 4647.205 I. &I. Pearson and C. S. Garner, J . Phys. Chem., 1961, 65, 690S H A R P : THE T R A N S I T I O X ELEMENTS 127gen atoms together with one tungsten atom.206 On acidification of tungstatesolutions there is immediate polymerisation to the [HW,02,15- Themagnetic susceptibilities of the lower tungsten oxides, WO,, have beeninterpreted in terms of a general model in which (3 - x) oxygen atoms havebeen removedfrom the W0,lattice to leave 2(3 - x) electrons in the conductionbands of the host lattice.208Manganese, Technetium, and Rhenium.-Structural studies onMnI1[MnJ1( OH2)HY],,8H20 (H4Y = ethylenediaminetetra-acetic acid) haveshown that half of the manganese atoms are seven-co-ordinate witha co-ordin-ation arrangement similar to that found in the NbF72- Potassiumpermanganate has long been known to dissolve in sulphuric acid to give a greensolution and it has now been suggested that this contains the Mn03+ ion.210Fluorination of most manganese compounds at 550" in a stream of fluorinegas gives the blue tetrafluoride ; the new tripositive complex fluorides KMnF,and RbMnF, are obtained by reducing KMnF, and RbMnF, with hydro-gen.211 By contrast with the fluorides the higher manganese chlorides areextremely unstable.Manganese dioxide and hydrogen chloride react incarbon tetrachloride to give a dark green compound which can be extractedinto ether.It cannot be isolated in pure form but gives (Et4N)2MnCl,with tetraethylammonium chloride.212 Some of the major advances intechnetium chemistry have been described under the headings of carbonylsand complexes with aromatic systems. A study has been made of thecomplex technetium cyanides : technetium dioxide dissolves in aqueouspotassium cyanide to give a solution from which Tc,[Tc(OH),(CN),] can beisolated ; technetium-(Iv) or -(VII) species in cyanide solution are reduced bypotassium amalgam to give green K,TCI(CN)~ which appears to be verysimilar to the corresponding rhenium compound.213 The first technetiumfluoride, the golden-yellow hexafluoride, m.p.33", has been prepared bythe action of fluorine on metallic technetium.214 Rhenium chemistry hasbeen the subject of a r e v i e ~ . ~ l , Perrhenic acid reacts with tertiary phos-phines and acids, HX, in ethanol to give ReOL2C13, ReO(OEt)L,Br,, andReO(OEt)L,I,. ReOL2C12 is converted into ReO( OEt)C12L2 when boiledwith ethanol. 216 Two types of rhenium-containing perovskites have beendescribed. The series A1x(B110.,ReV10.,)03 results from the interaction ofthe appropriate metal oxides, whilst rhenium metal reacts with a mixtureof barium and alkali-metal carbonates to give Ba(M10.,ReV11,.,)0,.217206 V. I. Khitrova and Z . G. Pinsker, KristallograJiya, 1960, 5, 711 [679].207Y. Sasaki, Acta Chem. Scand., 1961, 15, 175.208 M. J. Sienko and B.Banerjee, J . Amer. Chem. SOC., 1961, 83, 4149.209 J. L. Hoard, B. Pedersen, S. Richards, and J. V. Silverton, J . Anaer. Chem. SOC.,210 I>. J. Royer, J . Inorg. iVuclear Chetn., 1961, 17, 159.211R. Hoppe, W. Dahne, and W. Klenim, Xatiirzuiss., 1961, 48, 429; R. Hoppe,213 ?T. S. Gill, Chem. and Ind., 1961, 989.213 W. Herr and K. Schwochau, Angew. Chena., 1961, '73, 492.214 H. Selig, C. L. Chernik, and J. G. Rlalm, J . Itzorg. Nuclear Chem., 1961, 19, 377.215 A. A. Woolf, Quart. Rev., 1961, 15, 371.216 C. J. L. Lock and G. Wilkinson, Chenh. and 1 ) ~ d . , 1962, 40; J. Chatt and G. A.Rowe, ibid., p. 92; cf. M. Freni and 1'. Valenti, J . Irtory. Nuclear Chem., 1961, 16, 240.217 A. W. Sleight and R. Ward, J . Amer. C'heni. SOC., 1961, 83, 1088; J.Longo andR. Ward, ibid., p. 2816.1961, 83, 3533.W. Liebe, and W. Dahne, 2. anorg. Chem., 1961, 307, 276128 INORGANIC CHEMISTRYRhenium has a high affinity for oxygen-containing ligands, and rhenium(1v)has been shown to form extremely stable complexes with organic hydroxy-acids.21s Rhenium trichloride reacts with N-dialkyldithiocarbamates to giveproducts ReCl,(NR2*CS,) which probably contain a bidentate dithiocar-bamate grouping.219Iron, Ruthenium, and Osmium.-Ultraviolet spectra and reactions withdimethyl sulphate to give the corresponding dimethyl-isocyanide complexessuggest that the product of the protonation of dicyanobis-o-phenanthroline-iron(=) and its 2,2'-bipyridyl analogue should be formulated as[phen2Fe(C=NH),]2 + ; the infrared spectra suggest that the protonationoccurs on cis-cyano-groups.220 The reaction between the amminepenta-cyanoferrate ion and azide or thiocyanate ions, which gives purple or bluesolutions, has long been used as an analytical method for detection of these.latter ions. The deeply coloured species have now been isolated as saltsand are the [Fe(CN),X]3- (X = N3, NCS) anions.221 The tetradentateligand As( CH,*CH,*CH,*ASM~,)~ forms complexes with iron(II), iron(rn),cobalt(m), nickel(II), and nickel(m) derivatives. The dipositive complexesare of the form M chel X2 and are six-co-ordinate; the tripositive complexesare again six-co-ordinate and are of the form [M chel X,]Y.222 Ethylene-dianiinetetra-acetic acid can act as a complexing agent to stabilise thepurple ferrate(vr) species produced by the action of hydrogen peroxide onferric hydroxide;223 in the complex RbFe(OH,)Y,H,O (H,Y =.ethylene-diaminetetra-acetic acid) the iron atom is seven-co-ordinate, having a co-ordination sphere in the form of a distorted pentagonal bi~yramid.~2~ Aseries of tetrahalogenoferrates(rr) has been prepared and it has been shownthat the FeX,2- anions are spin-free dy3dB3 complexes.225 There hasbeen oonsiderable interest in the interstitial compounds of ruthenium andthe other platinum metals. New borides and carbides MB,, M,B,, and MC(M = Ru and 0s) have been described,2Z6 and a full study of the platinum-metal arsenides has given the phases RuAs, RuAs2, OsAs2, Rh2As, RhAs,RhAs,, RhAs,, IrAs,, IrAs,, Pd3As, PdAs,, and PtAs,.227 Ruthenium metalreacts with fluorine to give a new, fairly involatile, hexafluoride.It is a darkbrown compound which decomposes to ruthenium pentafluoride and fluorinea t 200O.228 Anhydrous ruthenium tribromide has been prepared by inter-action of ruthenium metal and bromine; it is insoluble in water.229 Pre-21sB. Jezowska-Trzebiatowska and S. Wajda, Bul. Acud. polon. Xci., Ser. Sci.chim., 1961, 9, 57; B. Jezowska-Triebiatowska, S. Wajda, and W. Wojciechowski,&bid., p. 65.219R. Colton, R. Levitus, and G. Wilkinson, J., 1960, 5275.z20N. K. Hamer and L. E. Orgel, Nature, 1961, 190, 439.221B. Jaselskis, J . Amer. Chem. SOC., 1961, 83, 1082.222 G. A. Barclay and A. K. Barnard, J . , 1961, 4269.223G. L. Kochanny, jun., and A.Timnick, J . Amer. Chenz. SOC., 1961, 83, 2777.224 J. L. Hoard, M. Lind, and J. V. Silverton, J. Anier. Chenz. Xoc., 1961, 83, 2770.225N. S. Gill, J., 1961, 3512.226 C. P. Kempter and M. R. Nadler, J . Chem. PAys., 1960, 33, 1580; C. P. KempterZ27R. D. Heyding and L. D. Calvert, Canad. J. Chem., 1961, 39, 955.228 H. H. Claassen, H. Selig, J. G. Malm, C. L. Chernick, and B. Weinstock, J . Amer.229 S. A. Shchukarev, N. I. Kolbin, and A. N. Ryahov, Zhur. neorg. Khim., 1960,and R. J. Fries, ibid., 1961, 34, 1994.Chem. SOC., 1961, 83, 2390.5, 1900 [923]SHARP: THE TRANSITION ELEMENTS 129vious work on the species found in aqueous solutions of ruthenium(1rr)chloride has shown the existence of RuC12+ and of two isomeric forms ofRuCl,+; two forms of the neutral complex, RuCl,aq., have now been iso-lated.230 A solution of ruthenium( IV) in perchloric acid contains ruthenium-oxygen species with an average charge of 3-2.There is extensive formationof polymers but an Ru02+ ion has been identified.231 The green-colouredcompound that results from the action of iodide on osmium tetroxide inhydrochloric acid has been identified as either H[ OsI,(H,O)] or H2[ OsI,( OH)].Mixed halogeno-osmates(Iv), KOsCl,. are formed in the same reaction ;this anion, unlike Os162-, is fairly stable to hydrolysis.232Cobalt, Rhodium, and Iridium.-The American Chemical Society haspublished a monograph on the chemistry and metallurgy ofLigand-field theory predicts that for a series of octahedral transition-metalions arranged in the order of the field strength of the ligands there will bespin-free compounds at the low-field end and spin-paired compounds at thehigh-field end of the series.At some intermediate ligand field, spin-freeand spin-paired states should be in equilibrium. It appears that such anequilibrium occurs in di-( 2,6-pyridinedialdehyde hydrazone)cobalt(n) iodide,and the magnetic susceptibility can be interpreted in terms of an equilibriumbetween doublet and quartet ~ t a t e s . 2 ~ ~ Oxidation of pentacyanocobalt(rr)species with oxygen and ferricyanide gives the binuclear complexes[ (NC),CO~~~O,COI~~(CN)~]~- and [ (NC),Fe11CNCo1*1(CN)5]5 - but oxidation ofpentacyanocobalt(n) species with hydrogen peroxide, persulphate, or[ (NC),CO~~IO,CO~~~(CN)~]~- gives [ (NC),COIII(OH,)]~ - as the major product.The [(NC),CoI1I(OH2)]2- ion is polymeric in solution and in the solid andthere is no evidence for five-co-ordinate cobalt in any of these complexes. Asa contrast to these reactions, the pentacyanochromate(11) ion is oxidisedby both oxygen and hydrogen peroxide to give hexacyanochromium(m) spe-cies. 235 A crystal structure determination on [ (NH3),Co0,Co(NH,),][N03]5shows that the axis of the bridging peroxide group is perpendicular to theline joining the two cobalt atoms; the two cobalt and the two oxygen atomsare in the same ~ l a n e .2 ~ ~ Several new series of cobalt complexes have beenprepared. Bisoxalatoethylenediaminecobalt(rr1) salts and the correspond-ing malonato-complexes can be prepared by oxidation of cobalt(I1) acetate,potassium oxalate, or malonate, and ethylenediamine hydrochloride withlead dioxide ; the oxalatobisethylenediaminecobalt(rrr) ion can be synthe-sised similarly and all of these ions can be separated into their opticallyactive isomers.237 Each of the azido-complex ions [Co en,(N,),] +,[Co en,N,Cl]+, and [Co en2N3(0H,)l2+ exists as two forms which are230R.E. Connick and D. A. Fine, J. Amer. Chena. SOC., 1961, 83, 3414.231F. P. Gortsema and J. W. Cobble, J. Amer. Chem. SOC., 1961, 83, 4317.2s2 E. Fenn, R. S. Nyholm, P. G. Owston, and A. TUPCO, J. Inorg. Nuclear Chem.,233 R. S. Young [Ed.], “ Cobalt,” Rheinhold.Pub1. Co., Kew York, 1960.234R. C. Stoufer, D. H. Busch, and W.B. Hadley, J. Amer. Chem. SOC., 1961, 83,235A. Haim and W. K. Wilmarth, J . Amer. Chem. SOC., 1961, 83, 509.236 C. Brosset and N.-G. Vannerberg, Nature, 1961, 190, 714; of. A. A. VIEek, Trans.2s7 F. P. Dwyer, I. K. Reid, and F. L. Garvan, J . Amer. Chem. SOC., 1961, 83, 2285.1961, 17, 387.3732.FarmJay SOC., 1960, 56, 1137.130 INORGANIC CHEMISTRYpresumably cis- and trans-isomers. These complexes are important sincethey are widely used in the study of the kinetics of reactions of cornple~es.23~Cobalt(I1) chloride reacts with potassium selenocyanate in ethanol in thepresence of tetraphenylarsonium chloride to give (Ph,As),[Co(NCSe),]. Theinfrared and ultraviolet spectra of this complex and of complexes containingthe [Co(N3),I2- and [Co(NC0),l2- ions indicates nitrogen-cobalt bondingwith definite evidence for tetrahedral co-ordination about the metal in thelast two complex ions.239 In the series Copy,L, (L = SeCN, SCN, OCN)the selenocyanate and thiocyanate complexes have octahedral co-ordinationabout the metal with the ligands L acting as bridges.However, the cyanateis tetrahedral and this change in stereochemistry is believed to be associatedwith the small bridging capabilities of the cyanate ion occasioned by theabsence of d orbitals of appropriate energy on the oxygen at0m.2~~ Incontrast to these complexes which all contain cobalt-nitrogen bonds,Co(SCN),(Ph,P), is considered to be tetrahedral with the thiocyanate groupbonded to the cobalt through the sulphur atom.241 The phases in thesystems MC1-CoCl, have been identified as Li,CoCl,, M,CoCl, (M = Li, Na,K, Rb, Cs), MCoCl, (M = Li, K, Rb, Cs), M3CoCl, (M = Rb, Cs), Cs,Co2Clg, andCS,CO,C~,.~~~ Chlororhodates(II1) react with formic acid to give the greenrhodium(r) salt HRh(HCO,),,H,O ; air-stable pyridinium and ammoniumsalts have been isolated.243 The broad-line proton magnetic resonance spec-trum of the compound known as K3Rh(C,0,),,4,5H20 shows that it shouldbe formulated as K6[Rh(C,04)3][Rh(C,04),(HC204)( OH)],8H20 ; the corre-sponding monohydrate is K6[ Rh(C,O,), ][ Rh( C,O,),(HC,O,) (OH)],H,O. 244Rhodium metal burns in fluorine gas to give rhodium hexafluoride; this isthe &st known hexa-positive rhodium derivative; the solid is black and thecompound is red-brown in the gaseous state. ,45 The hexachlororhodate(1v)anion appears to be stabilised in a hexachloroplatinate(w) or hexachloro-palladate(1v) lattice ; it is blue-green in c o l o ~ r .~ ~ ~Nickel, Palladium, and Plathwlz.-Some reactions which lead to complexcyanides of zero- and uni-positive nickel have been investigated in detail.A mixture of nickel metal, mercuric cyanide, and potassium cyanide heatedto 500" in vacm gives K,Ni(CN), + K,Ni(CN),; Kai(CN), and KCN reactat 480" to give K,Ni(CN),, K3Ni(CN), is produced by heating togetherK,Ni(CN),, KCN, and nickel meta1.247 Nickel carbonyl reacts with dinitro-gen tetroxide in the gas phase to give Ni(NO,),; this is only the second238P. J. Staples and M. L. Tobe, J . , 1960, 4812239 A.TUPCO, C. Pecile, and M. Niccolini, Proc. Chem. SOC., 1961, 213; F. A. Cottonand M. Goodgame, J . Amer. Chem. SOC., 1961, 83, 1777.2 4 0 s . M. Nelson, Proc. Chem. SOC., 1961, 372.241 F. A. Cotton, D. M. L. Goodgame, M. Goodgame, and A. Sacco, J . Amer. Chem.SOC., 1961, 83, 4157.242H.-J. Seifert, 2. anorg. Chem., 1961, 307, 137; K. A. Bolschakov, P. I. Federov,and G. D. Agaschkina, Zhur. neorg. Khim., 1957, 2, 1115.243 I. I. Chernyaev, E. V. Shenderetskaya, and A. A. Karyagina, Zhur. neorg. Khirn.,1960, 5, 1164 [559].244A. L. Porte, H. S. Gutowsky, and G. M. Harris, J . Chem. Phys., 1961, 34, 66.245C. L. Chernick, H. H. Claassen, and B. Weinstock, J . Amer. Chem. SOC., 1961,346R. Kiriyama, K. Ogawa, and M. Azumi, J . Chern. SOC. Japan, 1961, 82, 328.247 S.von Winbush, E. Grismold, and J. Kleinberg, J . Amer. Chem. SOC., 1961, 83,83, 3165.3197SHARP: THE TRANSITION ELEMENTS 131known anhydrous transition-metal nitrite. 248 The reactions of nickel(@,palladium(rr), and platinum(n) complexes of dimethylglyoxime (H,DMG)and 2-pyridinaldoxime (HPAX) with acetyl chloride have been re-investi-gated. All of the dimethylglyoxime complexes give MI1( H2DMG)C1, deriva-tives plus the free diacylated ligand. The 2-pyridinaldoxime complexesare completely destroyed in the case of nickel; the palladium complex givesPd( CH,-CO-PAX)Cl, which can be readily hydrolysed to [ Pd( PAX)Cl], ;the platinum complex is diacylated to [ Pt(CH,=CO*PAX),]C1,.2*9 Bisethyl-enediamine-nickel(=) and -copper(=) salts react with acetone to give com-plexes (e.g., 21) which are formulated to contain C6The colour changes of the Lifschitz salts, Ni(m,eso-explained in terms of changes in the ligand field onthe axial positions of a tetragonal complex.It ispossible that these changes in field strength areCH2 (21)brought about by an anion which is not in the firstco-ordination sphere of the nickel atom.251 Potas-sium fluorosulphinate, KSO,F, is a suitable fluorinating agent for convertingcomplexes such as Ni(PC1,)4 into Ni(PF,),. The latter reacts with ammoniato give Ni[P(NH,),], which is converted into the polymer [Ni(PN),], byThe stereochemical configuration about the nickel atom in thecomplexes L,NiX, (L = Bun,PhP, BunPh,Py Ary1,P; X = C1, Br, I, SCN,or NO,) appears to be related to the number of phenyl groups on the sub-stituted phosphine.Triarylphosphine complexes are pseudo-tetrahedralwhen X = halogen but are presumed to be planar when X is a thiocyanategroup ; the butyldiphenylphosphine complexes are paramagnetic and pseudo-tetrahedral in the solid but dissolve in benzene to give a mixture of thediamagnetic and the paramagnetic form ; the dibutylphenylphosphine com-plexes are diamagnetic in the solid and have tram-planar str~ctures.~~3 Thecomplex [Me*As(CH,*CH,*CH,*AsMe,),]NiBr, contains five-co-ordinatednickel. The three arsenic atoms are in a plane with one bromine atomnormal to this plane.and above the nickel. The remaining bromine atomis depressed 20” below a position which would complete a square pyramidand it is suggested that if it were in the more normal square position therewould be considerable steric interaction with the terminal methyl groups onthe arsenic atoms.The palladium and the platinum analogue are ionic andhave the structures [M(arsine)Br]Br, and it is generally found that for thenickel group the occurrence of co-ordination number five is Ni >> Pd > Pt(for an example of five-co-ordinated platinum see ref. 261). Each ofthese metals gives complexes [M(arsine),][ClO,], in which the metal has248 C. C. Addison, B. F. G. Johnson, N. Logan, and A. Wojcicki, Proc. Chem. SOC.,1961, 306.249 R. A. Krause, D. C. Jicha, and D. H. Busch, J . Amer. Chem. SOC., 1961, 83, 528.250N. F. Curtis and D. A. House, Chenz.and Ind., 1961, 1708.251 S. C. Nyburg, J. S. Wood, and W. C. E. Higginson, Proc. Chem. SOC., 1961, 297.262F. Seel, K. Ballreich, and R. Schmutzler, Chem. Ber., 1961, 94, 1173.253C. R. C. Coussmaker, M. Hely Hutchinson, J. R. Mellor, L. E. Sutton, andL. M. Venanzi, J . , 1961, 2705; M. C. Browning, R. F. B. Davies, D. J. Morgan, L. E.Sutton, and L. M. Venanzi, J., 1961, 4816.CHMeC CMetunits joined in to act as tetradentate ligand~.~~Oly2-diphenylethylenediamine),( RCO,),, have been/ \ 2H,C”\ / “ C H 2 M IH2C--. N N ’ ‘ ,‘HZMelC, ,CMeI I132 INORGANIC CHEMISTRYoctahedral co-ordination from arsenic atoms. 254 Bisacetylacetonatonickel(11)is trimeric, each nickel atom having a co-ordination number of six;255 thistype of association has been used to explain the magnetic and spectralproperties of nickel(n) complexes of other diketones, salicylaldimines, andsalicylaldehyde.Green diaquodisalicylaldehydatonickel (n) is a monomerwith a normal trans-octahedral configuration. 257 A suspension of palla-dium(=) fluoride in selenium tetrafluoride is converted into CsPdF, byaddition of czsium fluoride; a solution of palladium(rr1) fluoride in thissolvent is readily oxidised to palladium(1v) by the action of bromine tri-Lithium metal reacts with platinum in vacuo or under argonto give a new phase TiPt, which is an extremely reactive catalyst.259 Struc-tural determinations on two compounds of what appears to be tripositiveplatinum have confirmed the view that compounds of this oxidation stateare generally built up from equiatomic mixtures of platinum-(@ and -(Iv).Pt enBr, contains Pt enBr, and Pt enBr, groups; the two series of Pt enBr,groups are linked by the other bromine atoms and there is considerablecharge transfer along the chain.Wolffrani's red salt should be formulated as[ PtIV( EtNH,),Cl,][ PtI1( EtNH2)4]C14,4H20.260 The tetradentate ligand (22)gives compounds of the type [Pt(arsine)X]Y (X = C1, Br, I, SCN; Y = C1,Br, I, SCN, ClO,, BPh,) with platinum@). These complexes contain five-co-ordinate platinum both in the solid and in solution, and a structuralstudy of the [Pt(arsine)I]+ cation shows that the co-ordination is in the.,PhASform of a trigonal bipyramid. The tridentate arsine (23) gives four-co-ordinated complexes of the type [ Pt(arsine)X]Y with platinum(I1)derivatives.261Copper, Silver, and Gold.-New methods have been described for thepreparation of some copper(1) salts in non-aqueous solvents. Cuprousoxide reacts with ammonium salts in liquid ammonia to give the [Cu(NH,),] +cation; the iodate is insoluble and can be obtained by metathetical exchange254 G. A. Mair, H. XI. Powell, and D. E. Hem, Proc. Chem. SOC., 1960, 415; G. A.Barclay, R. S. Nyholm, and R. V. Parrish, J., 1961, 4433.255G. J. Bullen, R. Mason, and P. J. Pauling, Nature, 1961, 189, 291.z66 F. A. Cotton and J. P. Fackler, jun., J . Amer. Chem. SOC., 1961, 83, 2818; J. P.Fackler, jun., and F. A. Cotton, ibid., p. 3775; H. C. Clark and R. J. O'Brien, Canad.J .Chem., 1961, 39, 1030; J. R. Miller and A. G. Sharpe, J., 1961, 2594.z57 J. M. Stewart, E. C. Lingafelter, and J. D. Breazeale, Acta Cryst., 1961, 14, 888.e5'3N. Bartlett and J. W. Quail, J., 1961, 3728.259 C. P. Nash, F. M. Boyden, and L. D. Whittig, J . Amer. Chem. SOC., 1960, 82,260 T. D. Ryan and R. E. Rundle, J . Amer. Chem. SOC., 1961,83,2814; B. M. Craven261 G. A. Mair, H. M. Powell, and L. M. Venanzi, Proc. Chem. SOC., 1961, 170; J, A.6203.and D. Hall, Acta Cry&., 1961, 14, 475.Brewster, C. A. Savage, and L. M. Venanzi, J., 1961, 3699SHARP: THE TRANSITION ELEMENTS 133wit8h lithium iodate. Cuprous ammines react with carbon monoxide togive unstable carbonyls CuX,CO,xNH, ;262 solutions of copper(n) salts inacetonitrile are reduced to copper@) by the action of metallicDi(pyridine-2-aldoximato)copper(11) is a complex in which hydrogen-bondformation confers extra stability on the actual complex in the same manneras in bisdimethylgl~oximatonickel(a).However, the hydrogen is still acidicand can be replaced by a silver ion to give a heterobinuclear chelate (24)which can be isolated as the p e r ~ h l o r a t e . ~ ~ ~ Magnetic and spectral studiessuggest that the triphenylphosphine oxide complexes CuL,X, are pseudo-tetrahedral but that the CuL42+ cation is square planar;265 however, themost definite information about stereochemistry can come only from X-raystructural determinations and full structures have shown unusual co-ordination arrangements in several copper salts. Diazoaminobenzene-copper(1) (PWN*NPh)Cu, is dimeric with pairs of diazoaminobenzeneM eC-C’C-MeMe-C\CMe-Cmolecules linked through copper atoms. The co-ordination about thecopper atoms is almost linear and although the copper-copper distance isonly 2.45 8 (cf. copper metal 2.55 8, copper acetate dihydrate 2.65 A)metal-metal bonding is considered not to be present.266 A complex acetyl-acetonato-o-hydroxyanilatocopper(n) complex which was previously for-mulated with three-co-ordinate copper has now been shown to have structure(25). The molecule is pseudo-dimeric with two types of copper atom:copper atom 1 is in square planar co-ordination whilst copper atom 2 isfurther bonded to an oxygen of another dimer and is five-co-ordinated.The Cu-Cu distance is 3.00 A and metal-metal bonding is not invoked;however, antiferromagnetic exchange interactions occur through the oxygenbridges and cause anomolous magnetic susceptibilities. 267 The complexesCu chel,(ClO,), (chel = o-phenanthroline or 2,Z’-bipyridyl) react with univa-lent anions to give five-co-ordinated species [Cuchel,X]+ (X = C1, Br, I,SCN, NO,, HCO,, CH,*CO,, PhCO,). The [Cudipy,I]+ cation has anapproximately trigonal bipyramidal configuration about the metal with theiodide in the equatorial plane; perchlorates [Cuchel,X][ClO,] are 1 : 1electrolytes in nitromethane whilst diperchlorates, Cu chel,(C10,),, are weak262R. Nast and C. Schultze, 2. unorg. Chem., 1960, 307, 15.26sB. J. Hathaway, D. G. Holah, and J. D. Postlethwaite, J., 1961, 3215.2e4C. H. Liu and C. F. Liu, J . Amer. Chem. SOC., 1961, 83, 4167.265D. M. L. Goodgame and F. A. Cotton, J., 1961, 2298.2seI. D. Brown and J. D. Dunitz, Actu Cryst., 1961, 14, 480.267 G. A. Barclay, C. M. Harris, B. F. Hoskins, and E. Kokot, Proc. Chem. SOC.,1961, 264; cf. M. Kishita, Y. Muto, and M. Kubo, Austral. J . Chem., 1957, 10, 386;1958, 11, 309134 INORGANIC CHEMISTRYelectrolytes with co-ordinated perchlorate groups. Many other perchlorato-complexes of this type have been recognised and salts of very strong acids(e.g., hexafluorophosphoric acid) can be prepared in which the perchlorategroup remains co-ordinatively bound whilst the other anion is present asa free ion.268 Royal-blue copper(@ formate is a dimeric molecule witheach copper atom bonded to four oxygen atoms in a plane and being furtherbonded to a fifth oxygen of a neighbouring molecule; there is no metal-metalbond.26s Five-co-ordinated copper is also found in Cr(NH3)6CUC15 in whichthe co-ordination sphere is that of a trigonal bipyramid with all of the Cu-Cldistances equal. 270 KCuF, has a pseudo-perovskite structure with threedifferent Cu-F distances (2.25, 1-96, 1.89 A), and it is clear that there mustbe very complex electronic interactions in the ions to give distortions ofthis type.271 The interactions between the alkali metals and the metalsof this group have been fully studied. No compound is formed with copper,and with silver a new phase, NaAg,, has been identified. Gold gives awhole series of new phases-Li : Au, 15 : 4 ; 3 : 1 ; 4 : 5 N a : Au, 2 : 1 ; 1 : 1 ;1 : 1 .272 Silver fluoroborate and hexafluorophosphate are readily preparedby reaction between silver@) fluoride and the non-metal fluoride in liquidsulphur dioxide.273 A whole series of silver(n) carboxylates have beendescribed as resulting from the oxidation of silver(1) species with persulphatein the presence of the appropriateZinc, Cadmium, and Mercury.-An X-ray study of zinc oxide which hasbeen doped by heating it in zinc vapour shows that many extra zinc atomsare taken up into the octahedral holes of the lattice. Most of these extraatoms are electrically ne~tra1.2~5 Previously there has been only oneknown example of five-co-ordinate zinc but it has now been shown thatboth (acac),Zn,H,O and NaZn(OH), have the zinc atoms surrounded bya distorted trigonal bipyramid of oxygen atoms. 276 Infrared spectralstudies on the complexes M en2C1, (M = Zn, Cd, Hg) suggest that in thesecompounds the diamine is acting as a bridge between two metal atoms.277(N2H5),Zn(S0,), appears to be representative of a whole series of salts ofthe hydrazinium cation. It is found that one nitrogen of each of thecations is co-ordinated to the metal which is six-co-ordinated with bondingfrom bidentate sulphato-groups. The proton is presumably attached to theun-co-ordinated nitrogen atom.278 BaZnO, reacts with hydrogen sulphide268 C. M. Harris, T. N. Lockyer, H. Waterman, G. A. Barclay, and C. H. L. Kennard,Nature, 1961, 192, 424; C. M. Harris and E. D. McKenzie, J . Inorg. Nuclear Chem.;1961, 19, 373.269 G. A. Barclay and C. H . L. Kennard, J . , 1961, 3289; cf. R. L. Martin and H.Waterman, J . , 1959, 1359.270M. Mori, Y . Saito, and T. Watanabe, Bull. Chem. SOC. Japan, 1961, 34, 295.271A. Okazaki and Y. Suernen, J . Phys. SOC. Japan, 1961, 16, 176.272G. Kienast, J. Verma, and W. Klemm, 2. anorg. Chem., 1961, 310, 143.273D. R. Russell and D. W. A. Sharp, J., 1961, 4689.274 E. Bogdan, M. Motas, and D. Giurgiu, Studii si Cercetari Sti. Chim. (Pi.!. Iasi),275G. P. Mohanty and L. V. Azhroff, J . Chem. Phys., 1961, 35, 1268.276E. L. Lippert and M. R. Truter, J., 1960, 4996; H. G. Schnering, Natzc~w~ss.,a7?G. Newman and D. B. Powell, J., 1961, 477.278C. K. Prout and H. M. Powell, J., 1961, 4177.1 : 2 - K : A ~ , 2 : 1 ; 1 : l ; 1 ~ 2 ; 1:4--Rb:Au,1:1; 1 ~ 2 : 1:4--Cs:Au,1960, 10, 15.1961, 48, 665; cf. D. E. C. Corbridge and E. G. Cox, J., 1956, 594S H A R P : THE TRANSITION ELEMENTS 135at 800" to give Ba,ZnS,; this complex has ZnS,-tetrahedra linked into chainsand the chains are held together by barium ions.279 It now seems extremelyprobable that solutions of cadmium metal in cadmium(@ halides containstable cadmium(1) species. The cations are polymeric, and a salt Cd,(AlCl,),has been isolated from such a solution.280 The infrared spectra of aqueoussolutions of cadmium cyanide complexes do not agree with polarographicmeasurements in showing the presence of a [Cd(CN),]2- ion; low concentra-tions of cyanide ion react with mercuric species to give polymeric ionscontaining more than one metal atom per cyanide grouping.281 Fromstudies of Raman spectra it is concluded that bis( trifluoromethy1thio)-mercury reacts with mercuric salts in solution to give CF,*S*HgX derivatives.Tetraethylammonium or alkali-metal halides give [ Hg( SCF,),X] - species. 282D. W. A. S.D. W. A. SHARP.A. G. SHARPE.27Q H. G. Schnering and R. Hoppe, 2. anorg. Chern., 1961, 312, 99.280 L. E. Topol and A. L. Landis, J . Amer. Chem. SOC., 1960,82, 6291 ; J. D. Corbett,281 R. A. Penneman and L. H. Jones, J. Inorg. Nuclear Chem., 1961, 20, 19.z8aA. J. Downs, E. A. V. Ebsworth, and H. J. Emeleus, J., 1961, 3187.W. J. Burkhard, and L. F. Druding, ibid., 1961, 83, 76

ISSN:0365-6217    

DOI:10.1039/AR9615800079

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

ORGANIC CHEMISTRY1. INTRODUCTIONA NOTEWORTHY feature of the theoretical section is t'he discussion, for thefirst time in these Reports, of electrophilic substitution at a saturated (singlybonded) carbon atom. Also careful consideration is given to acidity func-tions, to isotope effects, and to solvent effects ; nuclear magnetic resonancestudies now show every sign of becoming a matter of routine. Only verybrief consideration of free-radical chemistry has been possible this year forlack of space. The section on quantum organic chemistry covers theperiod 1959-61, which has been marked by much publication centred onintensive work on fundamental problems, and by the study of electron-spinresonance and nuclear magnetic resonance spectra, but without majoradvances in quantum organic chemistry itself.Among general methods, interest in hydroboronation is undiminished,and the Wittig olefin synthesis and related methods find valuable applica-tion.Vinyl-lithium has been successfully made and exploited, and photo-chemical preparative methods continue to show valuable developments.In the field of stereochemistry the greatest interest attaches to the studyand use of optical rotatory dispersion for establishing the stereochemicalenvironment of appropriate chromophores. A claim1 to have obtained the" first example of an optically active Grignard reagent " is also noteworthy,and studies of conformational problems continue to be very fruitful.Much work has been done on aliphatic unsaturated compounds. Im-proved methods are applied to the synthesis of long-chain olefinic acids;natural acetylenic acids continue to attract attention ; and various simpleacetylenes having functional groups directly attached to triply linkedcarbon are described. Carbenic intermediates have been used in synthesesof allenes, and the absolute configuration of mevalonolactone has beenestablished.There have been important developments in the catalytic trimerisationof acetylenic to benzene derivatives.Highly strained poly-t-butylbenzeneshave been prepared and found to have interesting properties, as has a newcyclic system, radialene (hexamethylenecyclohexane) , Xylylenes (quino-dimethanes) receive important consideration, as do cyclic polyenes withboth few, e.g., four, and many, e.g., twenty, carbon atoms.Activity in the field of alicyclic compounds is unabated, ranging fromthe preparation and study of stable di- and tri-arylcyclopropenium saltsand other cyclopropane derivatives to larger rings, especially fused-ringsystems; where complexities continue to be unravelled, and to sesqui- andtri-terpenes.In the terpene area the combination of classical organicchemical studies with physical methods (X-ray crystallography, nuclearmagnetic resonance spectroscopy, optical rotatory dispersion studies) hasyielded valuable results very expeditiously. Much has been done on theestablishment of relative and absolute stereochemical configurations.1 H. M. Walborsky and A. E. Young, J . Amer. Chem. SOC., 1961, 83, 2595McWEENY: QUANTUM ORGANIC CHEMISTRY 137There has been a great abundance of work on every aspect of hetero-cyclic chemistry, with theoretical and physicochemical studies playing animportant r6le.Some fascinating novel sulphur heterocyclic compoundsare reported : e.g., the 1,2-dithiolium cation, and 1,2,4,6-tetraphenylthia-benzene. Interest in the biogenesis of alkaloids continues ; the detailedchemistry of the yohimbine group receives attention; the structure ofechitamine chloride has been established by X-ray and chemical methods ;and an elegant synthesis of conessine has been achieved.There have been valuable developments in the study of the mechanismof reaction of simple members of the carbohydrate group, and the firstcrystalline 3-ketoseY ~~-xylo-3-hexulose has been prepared.Sugar sulphateshave received important attention and sugars with a sulphur atom in thering, e.g., D-xylothiapyranose, are reported for the first time. Methods ofisolating starch fractions without degradation have been notably improved,giving, for example, an amylose with molecular weight >106.The importance of physicochemical methods to the steroid field has beenincreased by the successful application of optical rotatory dispersionmeasurements ; and intramolecular radical reactions, especially photolyticreactions, are now important in this field. A total synthesis of (&)-cestroneby a group of Russian workers is reported, and steroid lactones continue toattract attention.The section on amino-acids, peptides, and proteins, covering a two-yearperiod, is rich in notable advances.A few examples are: the applicationof mass spectrometry to the analysis of protein hydrolysates; the use ofI , 1 ’- carbonyldi-imidazole and 2 -ethyl- 5-phenylisoxazolium-3-sulphonate forforming peptide bonds ; the synthesis of biologically active peptides andclose analogues, and the correlation of their structure with biological activity ;the synthesis of bradykinin; the elucidation of the chain sequence of bovineACTH, and ribonuclease, and of the complete sequences of the ct- andp-chains of human hEmoglobin.T. S. S.N. B. C.2. QUANTUM ORGANIC CHEMISTRYTms report is concerned with the three-year period 1959-61. During thistime, many aspects of molecular quantum mechanics have received atten-tion and several thousand papers have appeared: but the number of out-standing advances in what may properly be called “quantum organicchemistry ” has been comparatively small.This situation is not likely topersist and major developments may be expected during the next few years.It should be seen rather as a sign of even more intensive work on funda-mental problems, with a return of emphasis to small molecules and evensingle atoms. When the forging of new theoretical tools is complete, thereis little doubt that organic chemistry will claim some of the first rewards.The present situation in molecular quantum mechanics was nicelysummed up by Coulson, a t the 1959 Boulder Conference.1 QuantumConference on Molecular Quantum Mechanics,476.Rev.Mod. Phys., 1960, 32, 169138 ORGANIC CHEMISTRYchemistry is over thirty years old and “ it is not surprising that many of theplums have now been picked and really interesting and novel fruit is harderto come by.” Although there was a steady development of basic theory,really original applications appeared to be taking place in only four fields:(i) the interpretation of vibronic spectra, and related topics connectedwith equilibrium shapes of molecules and complexes; (ii) the electronicspectra of aromatic radicals and ions, including more especially electron-spin resonance (ESR) spectra ; (iii) the interpretation of nuclear magneticresonance (NMR) effects in terms of spin coupling through the electron dis-tribution; and (ivj ligand field theory, including, for example, the magneticproperties of complex ions.The “plums~’ in n-electron theory-which used to be dealt with inperhaps four of every five theoretical papers-have indeed been picked :the harvest is useful because it helps us to understand other molecularproperties, particularly those uncovered by radio-frequency and microwavespectroscopy ; but sophisticated calculations of n-electron wave functions,and their use in discussing resonance energies and reactivities, are no longerthe main preoccupation of the theoretical chemist. This feeling is reflectedin a number of recent reviews, by Kotani et u Z . , ~ LO~din,~ Hall,4 Pople,5and Preuss.6Selection from the many hundreds of papers with a direct bearing onorganic chemistry has been made to illustrate major developments, mainlyin three areas where progress is steady and a connected survey possible.Basic Theory.-GeneruZ.Until recently, quantum chemistry dependedalmost entirely on the molecular-orbital (MO) and the valence-bond (VB)method. In MO theory the electrons occupied molecular orbitals; invalence-bond theory they . occupied atomic orbitals (AO’s) with spinscoupled in such a way as to describe localized electron pairs (“ bonds ”).It was generally recognized that either approach, carried to conclusion,would yield the same exact wave function (see, for example, McWeeny ’)but that the molecular-orbital method was more practical in non-empiricalcalculations. Consequently, nearly all rigorous work was based uponmolecular-orbital wave functions of the form(1) = IZ“wlw2 * - * vN1,where yl, y2 .. . yN are molecular spin-orbitals (Le., molecular orbitals with aspin factor a or to describe positive spin or negative spin), $Zl indicates theoperation of making the orbital product antisymmetric, as required by thePauli principle. Most normal molecules have “ closed-shell ” ground statesin which each molecular orbital appears twice, once with an a- and oncewith a b-factor, and the ground state is then described by a single configura-tion of type (1) and indicated in the usual way, e.g., [ ls22s2] for the berylliumatom. This approximation is transcended by setting up functions of type2 M. Kotani, Y. Mizuno, K. Kayama, and H.Yoshizumi, Ann. Rev. Phys. Chem.,1958, 9, 245.P. 0. Lowdin, Ann. Rev. Phys. Chem., 1960, 11, 107.G. G. Hall, Reports Progr. Phys., 1959, 22, 1.J . A. Pople, Ann. Rev. Phys. Chem., 1959, 10, 331.6H. Preuss, Natumuiss., 1960, 4’7, 241.‘R. McWeeny, Proc. Roy. SOC., 1955, A, 227, 288McWEENY: QUANTUM ORGANIC CHEMISTRY 139(1) for " excited " configurations (e.g., [ls22s13s1] for the beryllium atom)and allowing them to mix with the one-codguration approximation.Many-configuration calculations continue on simple systems (useful surveyshave been given by McLean et d.,* and by Allen and Karog), but theyare slowly convergent and of somewhat academic interest to the organicchemist. In fact, as Coulson, Craig, and others first showed lo the applica-tions to organic molecules are on the whole disappointing.Non-empiricalcalculations along these lines have been concentrated, for obvious reasons,upon small molecules. Examples of interest to the organic chemist aremethane,ll acetylene,l2 methylene and methyl, l3 carbon monoxide,14 form-aldehyde,l5, water,16 nitric oxide,17 ammonia,18 CH3-, NH3, and OH3+,19CH, NH, OH,20 BH, CH, OH, FH, 21carbon dioxide and. acetylene,22C3, N3-, NO,+, HF,-. 23 Such calculations are important largely becausethey raise, and go some way towards answering, a variety of fundamentalquestions: what approximations will it be safe to make in discussing largermolecules? what form should a semi-empirical theory take? and what is thebest way of describing the electronic structure of a complicated molecule?One approximation of over-riding importance, essential when dealingwith large organic molecules, is that of " neglecting the inner shells "-moreprecisely, assuming that the nuclei and inner shells merely provide aneffective potential field for the valency electrons (or for a particular " group "such as the n-electrons).The Grst reasonably comprehensive discussion ofthis approximation was given by Parr and his c o - ~ o r k e r s . ~ ~ They showedthat if the wave function is written as an antisymmetrized product of twofactors, namely,in which @A is a wave function for the inner shell (the A shell) and aBdescribes the electrons of interest (the B shell), then it is mathematicallylegitimate to treat the B shell electrons alone, provided the field in whichthey move is properly determined from @*. The product form (2) is still* A.D. McLean, A. Weiss, and M. Yoshimine, Rev. Mod. Phys., 1960, 32, 211.sL. C. Allen and A. M. Karo, Rev. Mod. Phys., 1960, 32, 275.lo D. P. Craig, Proc. Roy. SOC., 1950, A , 200,474; 1950, A , 202,498; C. A. Coulsonand J. Jacobs, ibid., 1951, A , 206, 287; C. A. Coulson, J. Jacobs, and D. P. Craig, ibid.,p. 297; R. G. Parr, D. P. Craig, and I. G. Ross, J . Chem. Phys., 1950, 18, 1561.l1 R. K. Nesbet, J . Chem. Phys., 1960,32,1114; E. L. Albasiny and J. R. A. Cooper,Mol. Phys., 1961, 4, 353.l2 L. Burnelle, J . Chem. Phys., 1961, 35, 311; G. W. King, Canad. J . Chem., 1960,33, 365.l3 A. Padgett and M. Krauss, J . Chem.Phys., 1960,32, 189; G. W. King and G. L.Malli, Canad. J . Chem., 1961, 1652.B. J. Ransil, Rev. Mod. Phys., 1960, 32, 245; A. C. Hurley, ibid., p. 400.l5 J. M. Foster and S. F. Boys, Rev. Mod. Phys., 1960, 32, 303; P. L. Goodfriend,F. W. Birss, and A. B. F. Duncan, ibid., p. 307.IsR. McWeeny and K. Ohno, Proc. Roy. SOC., 1960, A , 255, 367.17H. Brion and C. Moser, Phys. Rev., 1960, 118, 675.l*H. Kaplan, J . Chem. Phys., 1957, 26, 1704.19H. Hartmann and G. Gliemann, 2. phys. Chem., 1959, 19, 29.2o M. Krauss and J. F. Wehner, J. Chem. Phys., 1958, 29, 1287.21 A. C. Hurley, Proc. Roy. SOC., 1959, A , 249, 402.22 A. D. McLean, J . Chem. Phys., 1960,32, 1595; A. D. McLean, B. J. Ransil, and23 E. Clementi, J . Amer. Chem. Soc., 1961,83,4501; J .Chem. Phys., 1961, 34, 1468.24 R. G. Parr, F. 0. Ellison, and P. G. Lykos, J . Chem. Phys., 1956, 24, 1106.= g[@A@BI, (2)R. S. Mulliken, ibid., p. 1873140 ORGANIC CHEMISTRYan approximation, but it is much less severe than an orbital form such as(1) since each factor may be a many-electrop function of high accuracy.Only calculation can reveal the limitations of this kind of approach butavailable results l6 do suggest that the inner shells can be (‘ separated off”in a rather satisfactory way and that they may be assumed to be virtuallyunchanged when the atoms form molecules. These are, of course, basicpremises of qualitative valence theory, but a convincing demonstration oftheir validity is a major problem of quantum mechanics. Here, as always,the task is to formulate the theory so that it recognizes qualitativelyestablished features of real molecules : the existence of “ loosely coupled ”electronic groups is such a feature and is succinctly and generally recognizedby wave functions such as (2).In later work along these lines, Lykos andParr 25 have analysed the basis of n-electron theory, providing considerablejustification for the usual practice of discussing the n-electrons by themselves.Since this work of Lykos and Parr, the validity of separating wave func-tions according to expression (2) has been examined more generally by Arai 26and by LO~din;~’ and the effective field for one group of electrons in thepresence of any number of other groups has been represented 2* in terms ofdensity operators, which allow a generalization of the Coulomb and exchangepotentials of simple molecular-orbital theory. Parks and Pam z9 havedeveloped the special case of separated electron pairs (e.g., localized bonds)in some detail: their theory is then closely connected with the earlier workof Hurley, Lennard-Jones, and Pople,30 though Parks and Parr are more*concerned with developing practical semi-empirical methods and have gonesome way in this direction in an application to formaldehyde.31 Theyillustrate the importance of introducing self-consistency by discussing thereorganization of the o-electrons when a n-electron is excited and, inparticular, its bearing on the n + n* transition energies.The results areof preliminary nature, and the calculations of it ‘much more empirical char-acter than those mentioned previously,l5 but further developments areexpected. As Boys 32 has remarked, an important feature of all suchwork is the search for “ molecular invariants ”-quantities (e.g., suitablydefined electronegativities, “ bond functions,” etc.) which vary little frommolecule to molecule and can ultimately be adopted as semi-empiricalparameters or “units of structure.” Further work with wave functionsof the product form (2) may be expected to shed light on the stereochemistryof organic molecules, including, for example, the classic problem of theethane potential barrier, referred to in some detail by Wils0n.3~ It canbe shown 28 that, although the primary interactions of different electronicgroups are electrostatic, there are also “ polarization ” and “ dispersion ”25P.G. Lykos and R. G. Parr, J . Chem. Phys., 1956, 24, 1166.26 T. Arai, J . Chem. Phys., 1960, 33, 95.27P.-0. Lowdin, J . Chem. Phys., 1961, 35, 78.28 R. McWeeny, Proc. Roy. SOC., 1959, A , 253, 242; Rev. Mod. Phys., 1960,32,335.29 J. M. Parks and R. G. Parr, J . Chem. Phys., 1958, 28, 335.3oA. C. Hurley, J. Lennard-Jones, and J. A. Pople, Proc. Roy. A~OC., 1953, A , 220,31 J. M. Parks and R. G. Pam, J . Chem. Phys., 1960, 32, 1657.3aS. F. Boys, Rev. Mod. Phys., 1960, 32, 296.a3E. B. Wilson, Adv. Chem. Phys., 1959, 2, 367.446McWEENY: QUANTUM ORQANIC CHEMISTRY 141effects, just like those appearing in the theory of intermolecular forces. Areview by Pitzer 34 is of interest in this connexion.A basic difficulty in constructing accurate wavefunctions of any kind (for a whole molecule or even for single bond) is thedescription of electron correlation, a subject thoroughly reviewed byLowdin.35 For example, the two electrons in a a-bond are not restrained, inmolecular-orbital description, from coming arbitrarily close together in spiteof their strong mutual repulsion.A method of admitting some degree of cor-relation which is now gathering ground is that of " splitting " each molecularorbital. Instead of both electrons being placed in the same orbital (k,describing the pair by [y(l)y(2)] x [spin function], they are allowed to occupydifferent orbitals, y and y', which tend to keep them apart : symmetry isrestored by using a wave function [y(1)y1(2) + y'(l)y(Z)] x [spin function]." Split-orbital " functions were introduced independently by Hylleraas 36and by E ~ k a r t , 3 ~ ~ who replaced the closed-shell helium configuration ls2 bythe " open shell " ls'ls'', bringing one electron closer to the nucleus (con-tracted 1s' orbital) and sending one further away (expanded 1s" orbital).Similar treatments of the two-electron bond go back to Coulson and F i ~ c h e r , ~ ~Lennard-Jones and P ~ p l e , ~ ~ ~ and Mueller and E~ring,~'' and have beenutilized recently by O-ohata 38 and Kotani et ~ 2 .3 8 ~ In essence, a generalsplit-orbital wave function may be written in the form (2) with an " a factor "and a ' ' P factor," determining respectively the density of a electrons(spin, +&) andThe usual (doubly occupied) molecular-orbital function, written in this way,gives identical a and #? densities : but for radicals and systems in non-singletstates this is not so, and it is the difference of the a and the #? density whichyields the (resultant) spin density observed in electron-spin resonanceexperiments.I n general, the single antisymmetrized product (3) is not aspin eigenfunction (as it is for a configuration of doubly occupied molecularorbitals, with zero total spin) but represents a mixture of states of variousmultiplicity. To describe a singlet ground state (S = 0) the " contamina-tion " by functions with 8 ;t 0 should be removed by means of a suitableprojection operator,39 but the calculations then become very heavy: theymay, however, be performed in certain cases.The first n-electron applica-tion, by Itoh and Yoshi~umi,~~ yielded a benzene ground-state energy veryclose to that obtained by Parr, Craig, and Ross l o who used extensiveconfiguration interaction. Dearman and Lefebvre 41 recently applied thismethod of “ different-orbitals-for-different-spins ” to the ally1 radical, withexceedingly satisfactory results. Similar calculations on naphthalene andits ions have been made by Hoyland and Goodman,42 and the general theoryhas been further developed by Pauncz, de Heer and LO~din.~3 Recentwork by Linnett and Dewar and their co-workers 449 45 depends on the samegeneral principles. We return to these topics in discussing calculations ofspin density in electron spin resonance applications.In dealing with increasingly elaborate wave func-tions for molecules it must be remembered that the function itself has nodirect physical or chemical interest : the significant quantities 46 are the elec-tron density and (to a smaller degree) the “ pair function ” which describeshow the motions of two electrons are correlated.In n-electron theory theelectron density is described in LCAO approximation by the well-knownmatrix of “charges ” and “bond orders,’’ whose elements indicate theamounts of (n) charge in the various atomic orbitals and the weights of the“ overlap densities ” which describe the bonds. This special example ofilr “ density matrix ” provides the basis of ‘‘ electron population analysis,”which originated some ten years agoY47 was further developed by M~lliken,~~and is now a standard feature of most non-empirical LCAO calculations onsystems of all kinds.In general, the elements of an LCAO density matrixindicate the electron “ populations ” of orbital and overlap regions definedby the atomic orbitals and yield a clear physical picture of the electrondistribution and the origin of various molecular properties (e.g., dipolemoments, bond polarities, chemical reactivities) . Various examples ofpopulation analysis have been published.49 Density matrix theory andsome of its applications were reviewed by McWeeny 28 at the BoulderConference.Finally, although openly empirical in its approach,the method of atoms in molecules 50 and its many variants deserve mentionunder this heading.The situation in 1958 was summarized in theseReports;51 since then a comprehensive review by Arai 52 has appeared. Arecent paper by Stewart 53 gives a particularly clear and simple expositionof the method and a useful commentary on its applicability.Semi-empirical Molecular-orbital Theory.-Under this heading we con-sider various approximate forms of n-electron theory, from crude HiickelPopulution analysis.Atom in molecules.theory to approximate configuration interaction 54 and self-consistent field 5 5(SCF) methods, and still rougher approximate work on the c-electrons ofsaturated molecules. Applications involving magnetic effects (electron-spinand nuclear magnetic resonance) appear in the next section.Notablereviews of recent developments have been given by L~nguet-Higgins,~~Hall,4 Pople,5 Hartmam~,~’ PreussY6 and F ~ e n o . ~ ~Perhaps the most ambitious effort to give a criticalevaluation of approximation methods in n-electron theory has been madeby Ruedenberg in six long papers.59 This is the culmination of othercareful comparisons of various methods, applied to polycyclic systems (frombenzene to ovalene) by Ham and RuedenbergY6O which do much to strengthenconfidence in the value of less sophisticated work with relatively old-fashioned tools. It has long been recognized that the success of varioussimple theories (e.g., free-electron model and Huckel inolecular-orbitalBheory), and their surprising measure of agreement, is a consequence ofmolecular “ geometry.” More precisely, Ruedenberg traces this back toit “ topological matrix ” with unit elements corresponding to nearest-neighbour links and zeros elsewhere.This describes the way in whichthe atoms are connected, and it determines the essential form of the molecu-lar orbitals, while the actual geometry (which is changed by distorting thesystem ; e.g., trans- to cis-butadiene) is introduced only through distant-neighbour interactions and is of secondary importance. The eigenvectorsof the topological matrix are the Huckel molecular orbitals which surviveso many theoretical refinements with so little change of form and usefulness.This work helps to provide a sound basis for models of the type developedby Pariser and Parr 54 and P ~ p l e .~ ~ Recent investigations of currentapproximations have also been made by Parr, Stewart, Lykos, Coulson andSchaad, and others.61The value of simplemolecular-orbital theory has again been strikingly demonstrated in work onthe precise equilibrium forms of conjugated systems, in particular on thepossible alternation of bond lengths in long polyenes. The observed ultra-violet spectra of long-chain polyenes cannot be reconciled with equivalenceof the bonds (Kuhn,62 Dewar 63) and, following O o ~ h i k i t , ~ ~ Longuet-Higginsand Salem 6 5 have now shown, by allowing properly for o-bond strain,144 ORGANIC CHEMISTRYthat a marked alternation of bond lengths is inevitable even in the infinitepolyene.In later papers the latter authors considered cyclic polyenes,66where alternation was again established, and long polyacenes,67 wherealternation was found to be unlikely. Anno and Coulson 68 have extendedsuch work fo graphite, finding that alternation does not occur for anyplausible parameter values. Such studies are important in connexion withthe contention by Clar et ~ 1 . ~ ~ that the benzenoid rings in polynuclear con-densed hydrocarbons often appear to be joined by single bonds. Aninteresting case of low-order connecting bonds occurs in biphenylene andsimilar compounds : in such cases it is again important, as Ali and Coulson 70show, to admit dependence of the resonance integral upon bond length (andhence order) and to carry the calculation to self-consistency.The correla-tion of bond lengths and bond orders seems to be receiving less attention, butCruickshank and Sparks have made a careful study of naphthalene, andaccurate electron-diffraction measurements are discussed by Bak and Hansen-N ~ g a a r d . ~ ~ It is now generally accepted that, as Coulson 7 3 first suggested,there is no single length-order curve and that hybridization is an importantfactor; the situation has been discussed by Trotter 74 and by Mu1liken;TsDewar and Schmeising 76 have also discussed the length-order relationship.With the appearance of Vol. 111, Pt. 2, of the “ Dictionary of Values ofMolecular Constants,” 77 Hiickel molecular orbitals and bond orders arenow available for all the commoner conjugated hydrocarbons and manyradicals : in many cases, polarizabilities and localization energies are alsotabulated. Huckel calculations on less common non-classical aromaticcompounds continue to be made 78 alongside the more refined calculations(e.g., by Mataga et ~ 1 .~ ~ on naphthalene and anthracene). However, whenappreciable charge shifts occur, as in non-alternant and substituted hydro-carbons and in heterocyclic compounds, simple molecular-orbital theorybecomes unreliable and it is desirable to use self-consistent-field or configura-tion-interaction methods. This raises certain difficulties in fixing an in-creased number of parameters, and work with this aim has continuedin a wide field and a t various levels. Brown and Heffernan 8o have useda form of self-consistent-field theory (developed in previous papers 81) onolleagues have made Pariser-Parrtype calculations on chloroazines 82 and self-consistent field calculations onformic acid.83 To cite still more representative examples, Julg andBonnett 84 have employed an improved LCAO method 85 to discuss fulveneand the carbonyl group.Other papers have dealt with o-quinones,86phenol,87 aromatic methylpyridines,89 purines, monochloro-pyridine~,~~ various nitrogen- heterocycle^,^^ carb~lines,~~ and furan, pyrrole,and thiophen.94 It is important in such calculations to show that a varietyof properties are satisfactorily accounted for by using the same parametervalues (cf. Amos and Hallg5).An apparently declining interest in hyperconjugation was to someextent revived by the Indiana (1958) C0nference,~6 at which notable con-tributions were made by Sutton, Dewar, Turner, and Streitwieser.Semi-empirical calculations (see, e.g., Pauncz et d 9 7 ) continue.There has been a great deal of work, which cannot be fully reported, inconnexion with ultraviolet spectra of aromatic compounds. forinstance, cites over 500 papers (many of them semi-theoretical), almostentirely from one year (1958), and gives a commentary on the work ofMoffitt and of Sidman and a list of their publications: their regular andbrilliant contributions in this field will be sadly missed. Other reviewshave been given by Porter 99 on triplet states, Herzberg loo on free radicalspectra, Mason ll1 on molecular spectra in general, Murrell 112 on charge-transfer spectra, Ramsay on molecular spectra,l13 and Brocklehurst et ~ 1 .1 1 4Very useful work by Mason 115 on nitrogen-heterocyclic compounds con-tinues. Progress in this field, by use of Pariser-Parr theory (along the linesof earlier work 116) is reported by Anno;l17 and most of the work citedin the last paragraph makes some reference to spectra. Considerable atten-tion has been devoted to n+n* transitions involving the lone pair ofa heterocyclic nitrogen atom; for example, Anno,lf7 and Goodman and hisco-workers, 118 have used a variety of semi-empirical methods. Perturbationmethods for dealing with the effect of substituents have also been developedby Petruska.llg Simple molecular-orbital theory has been applied to aceta-nilide by Baba and Suzuki,120 and to ketyls and related (ionic) compoundsby McClelland;121 Peacock 122 has discussed aniline, using a self-consistent-field method and allowing for bond-length variations.Larger molecules have also received attention, e.g., porphyrins byG ~ u t e r m a n , ~ ~ ~ and porphin by Kobayashi.12* Notable efforts at a deeperand less empirical level have been made by Green and Linnett 125 and byMcEwen ; 126 they consider a variety of nitrogen-oxygen compounds, includ-ing nitromethane, nitrogen dioxide, nitrosomethane, and nitrosamines.127Careful calculations on ethylene, also taking into the account the a-electrons,are reported by I'Haya 128 whose work is based on that of Lykos andPam.Environmental eEects were the subject of a Royal Society DiscussionMeeting,129 and the electronic spectra of radicals and ions in solution havereceived considerable attention.Murrell has considered molecular com-plexes 130 in a series of papers (as well as in his review 112) and also theeffects of protonation in acid solution l31 (see also Mataga and Mataga 92).Basic strengths (of purines, etc.) have been discussed by Nakajima andP ~ l l m a n , l ~ ~ and acidity by S t r e i t ~ i e s e r . ~ ~ ~ Removal of " forbiddenness "of singlet-triplet transitions by environmental effects (presence of a para-magnetic molecule) has been explained in two ways, by Hoijtink 134 andby Murrell, 135 severally. Solid-state applications also include notablework on the Davydow spectra of molecular ~rysta1s.l~~Aromaticity and reactivity.Valuable efforts have been made to clarifythe concept of aromaticity and its relation to chemical reactivity. Therecent book ‘‘ Non-benzenoid Aromatic Compounds ” 137 contains a valuablesurvey by Craig, and the concept has also been re-examined by P e t e r ~ , l ~ ~by Fukui et a1.,139 and by Vol’pin.140 There is much to be said 138 for areturn to the ‘‘ old-fashioned ” view, in which aromaticity is directly linkedwith reactivity, particularly in view of the uncertain experimental signifi-cance of the theoretical resonance energy. Unfortunately, the variousindices of reactivity-though they often show a convincing correlationwith chemical data-also have a somewhat obscure significance, since thefundamental theory of chemical reactions is still in a singularly primitivestate.Atom localization energies (Wheland 141) which relate to the “ locali-zation ” of 0,1, or 2 n-electrons OG a particular centre in a transition complex(and corresponding bond localization energies) are commonly used as reac-tivity indices, and methods of calculating these quantities have been dis-cussed by Koutecky 142 and by Baba.143 Simonetta 144 has discussed thenature of the activated complex, particularly in nucleophilic substitution,and Morita Onthe other hand, perturbation methods which make no reference to a transi-tion-state “ model ” (the reagent merely being regarded as perturbingthe molecule) still enjoy considerable popularity.Greenwood and Hay-ward 146 have shown how the-atom and bond polarizabilities may be calcu-lated in self-consistent-field approximation, obtaining results qualitativelysimilar to those obtained from Hiicbel theory. Perturbation methods havealso been developed by Das et ~ 1 . l ~ ’ and by Fukui et ~ ~ 1 . ~ ~ 8 One majordevelopment in this field is due to B r ~ w n , l ~ ~ who proposes developing earliersuggestions by Nagakura and Tanaka 150 for a new mechanism of aromaticsubstitution. Brown considers the initial steps in electrophilic substitutionto beE Ehas made elaborate calculations on the benzenium ion.attached tetrahedrally to a ring-carbon atom). * The theory is very flexible,different steps being rate-determining in dieerent cirbumstances.In hissecond paper, 149 molecular-orbital calculations are described and a new re-activity index (a “ Z value ”) is proposed. It turns out that the 2 valuesare related to the “ frontier ” densities introduced by Fukui et &.151 andseverely criticized by other workers. 152 On the other hand, Nagakuraand Tanaka 153 defend the use of the “ free valency,” not only for thenormal molecule (radical reactions), but also for its cation (electrophilicreactions) and anion (nucleophilic reactions), assuming that electron transfermay be the important step. Recent work in this field has been surveyed,with special reference to the extensive Japanese literature, by F ~ e n o , ~ ~ andPullman and Pullman have reviewed the application in bi01ogy.l~~ Itmust be confessed that the whole field is in a somewhat confused and unsatis-factory state, largely owing to our ignorance of the rate-determiningmechanisms.The difficult problems associated withthe theoretical treatment of saturated molecules still resist solution, butsome progress has been made.In addition to the more formal theory alreadyreported, much work has been done in the Japanese school. O-ohata 38has studied the electron-pair bond, using essentially a “ covalent-plus-ionic ”wave function in discussing the bond polarity and its relation to Mulliken-type electronegativities ; Nagahara 155 has discussed the carbon-carbon bondin particular; and Hnmano 156 has treated $he polarity of the C-H bond.Fukui et ~ 1 .l ~ ~ have used a general, but very primitive, molecular-orbitaltheory of saturated molecules along the lines proposed by Sandorfy 158 andlater Y0shizumi;~~9 a good correlation with experimental quantities isobtained but a considerable number of empirical parameters are required.The use of simplified models is also illustrated in the work of Franklin andLampel60 on C-H bonds in ionized hydrocarbons. The nature of theelectron-pair bond has been examined from a less empirical standpoint byShull. l6With the realization 162 that localized bond orbitals (BO’s) may beobtained by appropriate mixing of molecular orbitals, and with the decliningpopularity of valence- bond theory, the status of hybridization becomes lessclear and its introduction largely unnecessa.ry (except in simple pictorialdiscussions of structure).Nevertheless the traditional method of pointinghybrids along the bonds and setting up suitable electron-pair functions hasTheory of sccturated molecules.McWEENY: QUANTUM ORGANIC CHEMISTRY 149been used, not only in semi-empirical discussions, but also to obtain wavefunctions of high accuracy.16 It now seems probable that there will be somerevival of interest in hybridization. Murrell,la3 Gilbert and Lyk0s,16~ andGolebiewski 165 have recently given simple recipes for constructing hybridsby an alternative criterion, that of maximum overlapping, and the depen-dence of bond properties on hybridization (particularly in the light ofquadrupole-coupling data) has been discussed by Wilmhurst 166 and manyothers.Interpretation of Nucleax Magnetic and Electron Resonance EX€ects.-Impressive advances in this area continue and useful reviews have appearedrecently.Pople 5 has discussed recent work on electric and magnetic effectsin general, a field also reported by Buckingham.le7 Karplus has reviewedthe use of nuclear magnetic resonance in obtaining information onmolecular wave functions 16s and the general theory of weak interactions,l69and Brownstein 170 and Corio 171 deal with more chemical applications. Theinterpretation of the spin Hamiltonian has been discussed by Bersohn ;I72Weissmanf73 has also reviewed the uses of both nuclear magnetic andelectron-spin resonance spectroscopy. The underlying theory of electron-spin resonance is nicely illustrated in a review by Carrington and Longuet-Higgin~,17~ while Grechiskin 175 has made a useful survey of the experimentala,nd theoretical literature on nuclear quadrupole resonance.The excellenttextbook on high-resolution nuclear magnetic resonance by Pople, Schneider,and Bernstein 176 deserves special mention, two chapters being devoted tothe quantum-mechanical discussion of coupling constants and chemical shifts.The coupling of nuclear spins in a moleculeis usually described by a " spin Hamiltonian " which contains only nuclear-spin operators, with certain coefficients (the various coupling constants).The energies of different nuclear-spin states then appear as eigenvalues ofthe spin Hamiltonian (operating on a nuclear-spin function), just as the elec-tronic energies appear as eigenvalues of a Schrodinger Hamiltonian (operatingon an electronic wave function).It is now recognized that the couplingconstants are in fact determined by the ordinary electronic wave function(i.e., that nuclear spins are coupled via the electron distribution) and thatmuch information about the electronic structure can be obtained fromobserved values of coupling constants. The same is true in electron-spinresonance, where the operat'ors for the total (non-zero) electronic spin alsoNuclear magnetic reSonance.Magnetic Resonance," McGraw-Hill Book Co., Inc., New York, 1959150 ORGANIC CHEMISTRYoccur, along with electron-nuclear-spin coupling constants. Conversely,the prediction of coupling constants provides a sensitive test of theoreticalmodels and approximate wave functions.Calculations ab initio, along thelines followed by R a m ~ a y , l ~ ~ are usually prohibitively difficult but havebeen made for simple systems. For organic molecules it is usual to adopta semi-empirical approach such as that of McC0nnell,17~ which shows inparticular that proton-proton coupling constants are proportional toformal H-H bond orders: this result has been used with some success byWilliams and G u t o ~ s k y , l ~ ~ but, in the absence of precise wave functions,H-H bond orders cannot be estimated very reliably and the approach seemsbetter adapted to qualitative discussions. Another way of describing thepresence of H-H bond orders is to say that there is an appreciable deviationfrom the approximation of perfect pairing and it is natural that the valence-bond theory should be revived in this new context.This has been done byKarplus and Anderson la0 who discuss the H-H, H-F, and F-F couplingsin fluorinated ethanes and ethylenes. Karplus has also given a valence-bond interpretation of proton-spin coupling through the n-electron distribu-tion of conjugated molecules,lsl while McConnell la2 has used the method toinfer that coupling constants for protons separated by an even number ofC-C bonds are negative. The valence-bond theory has also been developedby Hiroike la3 and by Alexander.la4 A study of the molecular-orbital ap-proximation led to the conjecture by Pople, Schneider, and Bernstein 176that nuclear spin-spin coupling was dependent on a correlation of electronicspins. I f an electron of spin +Q is at one nucleus, the probability of find-ing a second electron at the other nucleus depends on whether its spin isalso +$ or -8; the '' contact " coupling of each electron spin with its nucleusthen transmits the effect to the two nuclei.This result has been establishedunder very general conditions by McWeeny and Mizuno 185 and makes ituseful to d e h e a '' spin-coupling density "-adding to the list of densities(electron density, " pair " density, spin density) which are, in principle,observable and have a greater intuitive appeal than the wave function itself.Apart from its fine structure, due to nuclear spin-spincoupling, the position of a resonance peak depends on the magnetic fieldat the nucleus: this differs from the applied field, owing to induced diamag-netic currents in the electron distribution, and the peak may therefore beshifted bodily according to electronic environment.This " chemical shift "is another source of useful information about the electron distribution.Ramsay's original work,186 again, does not lend itself to semi-empiricaldevelopment; but the theory due to Pople 187 gives some promise of dealingChemicaZ shifts.p. 11McWEENY: QUANTUM ORGANIC CHEMISTRY 151with shiffs in terms of local “ atomic ” contributions. Work along suchlines has been pursued by Karplus and Das 188 and by Fi~man.18~ Alter-native treatments, in which second-order perturbation theory is avoided,have been developed by Stephen190 and by Sinha and Mukherjee,191 andhave been used in non-empirical calculations by Das and Bers0hn.1~~Among many other, more empirical applications are those by Fraenkelet al.,193 which suggest a proportionality between C-H proton shift andthe charge on the carbon atom, and also those by Katayama et al.forstilbenes. lg4Effects arising from nuclear quadrupole momentsshed light on the field gradient at the nucleus, arising from the electrondistribution. The subject has been reported on briefly by Buckingham,l67reviewed by G r e ~ h i s k i n , ~ ~ ~ and surveyed in the book by Das and Hahn.195Since the early work of Townes and Dailey Ig6 many papers have appearedon the relationship of quadrupole coupling constants to bond polarity andhybridization parameters ; some recent attempts are due to Wilmhurst,l66Karnan0,1~~ and 0-0hata.3~ Recent work on specific molecules includesthat of Hooper and Bray lg7 on various substituted hydrocarbons (bothsaturated and conjugated); that of Dailey 198 on alkyl halides; and a usefulsurvey by Bersohn 199 of deuteron coupling constants.Efforts have beenmade (e.g., by Brion and Moser,200 and by Kato 201) to calculate couplingconstants non-empirically from molecular-orbital wave functions ; but, asthe work of Brion and Moser 2oo and of Richardson 202 shows, it is exceed-ingly difficult to get reliable information about the field at the nucleus, andagreement with experiment may often be largely fortuitous.One most satisfactory development in the lastfew years has been the interpretation of electron-spin resonance experimentsby using the concept of spin density.This is mostly simply defined 2% 185in terms of the densities, Pa and Ps, of electrons of spin ++ and spin -4.The electron (i-e., charge) density is Pa + Ps, while the spin density isPa - Ps and is proportional to the x-component (M,) of total spin (vanish-ing in a singlet state): the normalized spin density, p,, introduced byM~Connell,~O~ results when (Pa - Ps) is multiplied by 1/(2Ms). The couplingQuadrupole coupling.Electron-spin resonance.152 ORGANIC CHEMISTRYof electron and nuclear spins is completely determined by py, mainly by itsvalue at the nuclei (the isotropic, " contact " coupling) and near the nuclei(the anisotropic, dipole-dipole coupling, which averages to zero for rapidlytumbling molecules).When the spin density, p,, at a point is negative thelocal spin angular momentum is in opposition to the overall spin, M,. Inthe simple molecular-orbital description of a radical, p, is everywhere posi-tive, indicating the odd-electron density which may vanish on certainatoms ; negative densities then arise at these points when configurationinteraction is 204 With an LCAO approximation the spindensity appears as a weighted sum of atomic-orbital contributions, and thecorresponding " spin populations " (cf. " electron populations ") give asimple picture of the distribution of unpaired spins and of the origin of thehyperfine couplings.The kind of information obtained from electron-spinresonance experiments is well illustrated by the work of Gordy and hisschool on N-acetylglycine 205 and glycylglycine. 208 Calculations of spindensity in aromatic radicals and ions are rapidly becoming standard, simplemolecular-orbital theory with configuration interaction giving a fair pictureeven of the negative densities. Since a single antisymmetrized ' function,with an cc-factor and a #?-factor (e.g., different orbitals for diflFerent spins),does not represent a pure spin state, its use in predicting spin propertiesis open to criticism. On the other hand, the one-determinant wave function(to which the orbital form is equivalent) is much more convenient than theprojected function which would ideally be used. Efforts have been made 207to justify the one-determinant form and work with functions of this kindcontinues,2o8 but there is still some controversy as to the most reliablemethods.Examples of recent calculations are provided by Lefebvre et aL209(perinaphthenyl, triphenylmethyl), Hoij tink et aiL210 (pyrene negative ion),and Vincow and Fraenkel 2J1 (semi-quinone ions). Semi-empirical self-consistent-field theory has been developed for this purpose by McLachlan 212who also succeeds in explaining the general similarity in electron-spinresonance spectra of positive and negative alternant ions.213 The valence-bond theory has also proved useful in spin density calculations, notablyin the hands of Gutowsky and his collaborators.214 Anisotropic hyperfinecouplings, inferred from single-crystal spectra, are obtained by averaging thedipole-dipole operator over the spin-density function and have been suc-cessfully treated by McConnell and Strathdee.215 The general theory ofboth isotropic and anisotropic electron-nuclear coupling effects has also beendiscussed by McWeeny and Mizuno.lg5 Accurate numerical calculationsRIDD: THEORETICAL ORGANIC CHEMISTRY 153have been attempted with some success, notably by Brion and Moser,200Lin et aZ.,216 and Yamazaki et aZ.217 (NO molecule).Finally, the work reported in this section has many ramifications ofmore specialized interest. As a closing example, there is a growing interestin the " zero-field splitting " of molecular Zeeman levels due to electron-electron spin-dipole coupling.This effect, first observed by Hutchison andMangum 218 for the phosphorescent triplet state of naphthalene, has nowbeen widely discu~sed.21~ I n this way it is possible to obtain detailedinformation about the electron distribution in individual molecules inexcited states-a remarkable feat. Indeed, the quantum theory of electronand nuclear resonance efTects is advancing at a rate reminiscent of the earlythirties, making sense of a vast amount of detailed information and shed-ding new light on the electronic structure of organic molecules and radicals.R. McW.3. THEORETICAL ORGANIC CHEMISTRYPart IIT is convenient to outline first some developments concerning acidityfunctions and isotope effects, for these have a bearing on many mechanisticproblems.Acidity Functions.-This subject was last reviewed in 1959. Manystudies of indicator equilibria have since been reported, relating to theH0,2 and J , (= HR = C,) functions.However, probably the mostsignificant development comes from the increasing evidence that indicatorsof the same charge type can show large differences in the acidity dependenceof protonation equilibria. Thus the protonation of secondary and tertiaryamine~,~ of 1,3,5-trimetho~ybenzene,~ and of some azulenes 7 has beenshown to deviate from predictions based on the conventional H , acidityfunction. Related discrepancies involving the H- function in aqueoushydrochloric acid are apparent from recentThe effects of medium on the protonation of amines have been discussedin terms of the hydrogen bonds formed by the conjugate acids but, ingeneral, the structural features that cause deviations from typical " H ,behaviour " do not seem to be understood.Over the same range of acidity,the protonation of 1 -nitroazulene varies with the acid concentration ina different way from that of 1,3,5-trimetho~ybenzene;~ it therefore seemsimpracticable to define an acidity function in terms of the protonation ofaromatic rings.The deviation of the rates of acid-catalysed reactions from a simpledependence on the H , function has been often taken as evidence for thepresence of a water molecule in the transition state.On this matter, theoriginal Zucker-Mammett hypothesis has been extended by Bunnett 9 ina way that attempts to distinguish between the r6le of water as a nucleophileand as a proton-transfer agent; this mechanistic distinction is based on theslope of a plot of log (k + H,) against log aHz0 (see p. 164). However, anysuch approach implies that the acidity-function measurements are appro-priate for the substrate used. It is therefore not surprising that thesearguments break down when applied to proton transfers to aromatic rings;several examples are now known where such proton-transfer reactions showa simple H,-dependence under conditions where it seems very probablethat a water molecule is involved in the transition state.6, 10 The enolisa-tion of acetone was recently considered 11 to show an No-dependence, butredetermination l2 of the basicity of acetone makes this conclusion improb-able.Further measurements of the H , function in basic media have beenreported.13 The strongly basic properties attributed to aqueous hydrazineand aqueous ethylenediamine are not reflected in the rate of hydrogen-exchange between molecular hydrogen and the medium.l4Isotope Effects involving Deuterium.-These can be divided into threeclasses : primary effects derived mainly from changes in the vibrational fre-quencies of a hydrogen nucleus during transference to another centre ;secondary effects associated with the substitution of deuterium for hydrogena t a position not undergoing the reaction studied; and solvent effects arisingfrom differences between water and deuterium oxide as reaction media.In kinetic studies, all three types of isotope effect sometimes combine toproduce the observed result; the last two effects also influence equilibria.These have been reviewed by Westheimer,15with special reference to the interpretation of low kE/kD ratios.Interestcontinues in the possible contribution from proton tunnelling,16 and theunexpectedly large isotope effect on the activation energy of one eliminationreaction has been interpreted in that way.17 Swain and his co-workers 18, Ishave pointed out that the kH/E, ratios for hydride-ion transfers appearto be much less sensitive to substituent effects than those for proton trans-fers; this has been suggested as a mechanistic criterion and has been appliedto the oxidation of alcohols 18 by bromine, and to the decarboxylation ofsubstituted benzoylacetic acids.l9Secondary isotope effects. It has been clear for some time that severalfactors must be involved in determining the direction and magnitude ofsecondary isotope effects.20 Halevi's arguments 21 concerning the greaterinductive electron-donation by deuterium are supported by recent evi-dence 22 that the ring deuteration of benzoic acid and phenol lowers theacidity of these molecules; in the same way, deuteration increases the extentof ionisation of triphenylmethyl chloride.23 However, deuteration of themethyl group of acetophenone lowers the basicity of the molecule;24 a resultthat corresponds to the decrease in the rate of some solvolyses when p-hydrogen atoms are replaced by deuterium.25 This has generally beenattributed to the greater hyperconjugative electron donation of p-hydrogenatoms compared with #&deuterium a t o m ~ , 2 ~ ~ but an alternative explanationconcerning the lower non-bonded repulsions of deuterium atoms has alsobeen put forward.26 The importance of such non-bonding interactionsreceives support from evidence that some /?-deuterium isotope effects arisefrom a difference in the entropy of activation;27 this is interpreted in termsof the relative potential barriers for rotation of CH, and CD3 groups.27 Insome solvolyses, y -deuterium isotope effects are of similar magnitude butopposite direction (E&, < 1) to those for the p-position;28 these havealso been discussed in terms of molecular vibrations.28The inductive contribution to the isotope effect is considered to arise fromthe difference in the lengths of the C-H and C-D bonds resulting from theanharmonicity of the potential curve.21 However, the contribution fromnon-bonding interaction has been attributed 26 to the difference in the ampli-tudes of vibration of C-H and C-D bonds; to a first approximation, this isindependent of the anharmonic shift in bond length.Sotvent isotope evffects. A simple set of rules for predicting the solventisotope effect on acid-baae equilibria involving oxygen acids has been putforward by Bunton and Shiner.29bic The calculations are based on a struc-tural treatment of solvation and involve the number and stretching fre-quencies of the hydrogen bonds arising from the solvation of the reactantsand the products.to the kineticisotope effects expected for certain model transition states ; nucleophilicsubstitution by hydroxide ions, 29b reactions at ca'rbonyl groups,29b and pro-ton transfers from hydroxonium ions have been treated in this ~ a y . 2 ~ ~Primary isotope effects should also be important in the last reaction, butfrom a consideration of the solvent isotope effect, it is estimated that themaximum value of JcH,o/kDIo should be about 3 ~ 6 . ~ ~ ~ The solvent isotopeeffect for proton transfers to olehs has also been discussed by Willi.30The dependence of reaction rates and equilibria on the fraction ofdeuterium oxide in its mixtures with water presents a more complex prob-lem, and the relative importance of the factors concerned do not yet seemto be clearly established.31 However, considerable attention has beengiven to the type of variation expected for different kinds of transitionstate.32 Other studies of solvent isotope effects in solvolyses concern thetemperature dependence 33 and the influence of neighbouring gr0ups.3~ Thebase-catalysed loss of tritium from phenylacetylene in water and deuteriumoxide has also been studied 35 (cf. p. 170).Aromatic and Pseudo-aromatic Compounds.-Pseudoaromaticity. Hept-alene 36 (1) illustrates clearly the instability of pseudo-aromatic systems 37This approach has been extended 2 9 b 3although the conjugate acid (2) appears to contain an aromatic ring.36 Thisinstability contrasts with the significant aromatic stability of the relatedcompound (3), as indicated by reactions of a dimethyl derivative.38 Theproperties of this conjugated system, and the less stable pentalene derivative(4) have been discussed by Asgar Ali and Coulson.39 From valence-bondcalculations, they conclude that structure (3) should have a symmetricalground state and thus be aromatic, while structure (4) should be pseudo-aromatic.This type of tricyclic compound appears to offer some difficultiesto the simple rules for distinguishing between aromatic and pseudo-aromaticsystems, essentially because of the significant contribution of structurestypified by ( 5 ) to the ground state of the molecule (cf.ref. 37, footnote,p. 3179). The nuclear magnetic resonance spectrum of a dimethyl derivativeof compound (3) does not suggest tt completely aromatic str~cture.38~The recent evidence that the organic ringsin dibenzenechromiuin contain alternate single and double bonds 4O has ledto some discussion concerning the ease of rotation of the r i n g ~ . ~ l The firstsubstitution has been effected with this compoundY42 giving the diester (6),as a result of metallation, reaction with carbon dioxide, and esterification.The text 42 hints that the product may be a mixture of isomers as a resultof the restricted rotation of the rings. From the solvolysis of such com-pounds as methylferrocenylmethyl acetate (7), it appears that the metallo-cene group greatly facilitates SN 1 substitution a t adjacent centres ;43 -45this has been explained by considering the resulting carbonium ion as ametallocene derived from a cyclopentadienyl radical and a fulvene positiveion (8) .44 Stereochemical studies indicate that the facilitation of ionisationis greatest when the leaving group is trans to the metal in the transition~tate.~3, 45Nuclear nzagnetic resonance measurements 01% aromatic systems ; chemicalshifts. Two important factors in determining the chemical shift are theinduced ring current in the aromatic system and the local electron density.The first factor has been used as an estimate of the aromaticity of the ring;in this way it has been suggested that 2-pyridones have about 35% of thearomaticity of benzene.46 Proton chemical shifts and more recently 13C-chemical shifts have also been used to obta,in information on n-electrondensities.Nuclear magnetic resonance measurements on the symmetrical mono-cyclic systems C7H,+, C,H6, C5H5-, and C8Hg2- have shown4' that theIH- and 13C-chemical shifts are related approximately linearly to the n-elec-tron density.However, other factors can modify the relative chemicalshifts observed in more complex molecules. In bicyclic systems the chemicalshifts in one ring are influenced by the induced ring current in the other,and in monosubstituted benzenes the 13C- and IK-chemical shifts at theortho-positions (and the 13C-chemical shift at the l-position) are influencedby the magnetic anisotropy of the s u b s t i t ~ e n t .~ ~ The proton chemicalshifts can also show large and inexplicable solvent effects.49Nevertheless, the recent measurements of 13C-chemical shifts are suffi-cient to show that this may be the most sensitive way of probing the n-elec-tron densities in isolated aromatic molecules. As expected, the range ofchemical shifts in alternant aromatic hydrocarbons is ~Iight,~O but a muchgreater variation occurs with azulene 4 7 9 50 and this has led to a set ofn-electron densities in good agreement with recent calculations.51, 52 Inmonosubstituted benzenes the 13C-chemical shifts are small at the rneta-position, and generally as expected at the para-positi~n;~~, 53 at the ortho-position some apparent anomalies occur; thus the n-electron density at theortho-position in nitrobenzene appears to be greater than 53 Themost recent calculations suggest that the n-electron density in this positionshould be a little less than unity.54Related studies of proton chemical shifts have concerned a~ulene,~7 thepyridine ring and trisubstituted benzenes.56 In a general reviewof o-values, Taft 57 has discussed the variation of the lgF-chemical shiftswith the inductive (oI) and resonance (a,) parameters of other substituents.Electrophilic Aromatic Substitution.-Probably the most rapidly develop-ing section of aromatic substitution concerns the electrophilic replacementof atoms or groups by hydrogen, and this subject, together with nitrationand halogenation, is discussed separately below.On the theoretical side,the concepts of frontier electron density and superdelocalisability have beenapplied to non-alternant hydrocarbons by Fukui and his collaborators 68and a critical comparison of the different reactivity indices has been pub-lished. Empirical approaches to the influence of substituents continueto be developed, usually on the basis of the Hammett equation 57, 6o but inone case with a different mathematical form 61 that reflects the earlierqualitative division into polarisation and polarisability effects.Further mechanistic studies have been published on sulphonation, 62 andthe partial rate factors for the sulphonation of toluene have been redeter-mined.63 Kinetic studies have been reported on the acetylation of anisoleby acetic acid in the presence of boron trifluoride 64 (this reaction may in-volve Ac+ ions), and on the further isopropylation of isopropylbenzene.65Engelsma and Kooyman 66 have discussed some interesting orientationalproblems involved in the gas-phase chlorination of aromatic compounds,including the extensive meta-substitution in diphenyl ether.Mechanistic studies, mainly by W.N. White and his co-workers, havebeen carried out on the O r t ~ n , ~ ~ Claisen,68 benzidine,Gg and nitramine 7urearrangements. Substituent effects on the Claisen rearrangement lead toa rather complex picture of the transition state, involving many different,kinds of contributing structure.68 There appear to be two independentacid-catalysed mechanisms for the benzidine rearrangement of N-methyl-hydrazobenzene:6g one is of the fist order in hydrogen ions and the otheris of the second order.solutions in aqueous methanol.I n the nitramine rearrangement deuteratioriof the ortho-positions does not change the ortho : para ratio.70 This resultand the kinetic effects of substituents are considered MeIrepresented by structure (9), together with other con- A r " *1H tributing structures, including further electron transferto the nitro-group. In the Reporter's view it is also (9)possible to interpret the new results in terms of the earlier mechanism forthis reaction.71Kresge and Chiang lo have shown that theprotodetritiation of 1,3,5-trimethoxy-Z-tritiobenzene in aqueous acids isgeneral acid-catalysed and obeys the Bronsted relationship over an unusu -ally wide range of acidity, including the acids H30+, H*CO,H, and H,O.There is no evidence of base-catalysis.Since the overall reaction path mustbe symmetrical these results indicate that the transfer of a proton by aBronsted acid and the acceptance of the tritium nucleus by a Bronsted baseare not synchronous; the intermediate (10) is apparently formed and takesThis conclusion applies to feebly acidic ([H+] Mto provide evidence for a radical-ion intermediate aspart in the forward and the reverse reactions as shown. In related reac-tions, Olsson 72 has discussed how the rate-coefficient ratio ( L 1 / k 2 ) dependson the point of substitution and on the nature of the isotopes being ex-changed; he concludes that there is a significant isotope effect on the orienta-tion of hydrogen-isotope exchange.A logarithmic plot of the rate of protodetritiation of 1,3,5-trimethoxy-2-tritiobenzene against Ho has a slope of unityY6 but the general acid-catalysis observed at lower acidities makes it difficult to believe that theunit slope arises from a pre-equilibrium proton transfer to the substrate.This throws further doubt on some of the arguments used to support the A-1mechanism of hydrogen isotope exchangeY73 and there now seems no firmevidence for this reaction path. However, Melander has given some reasonswhy the A-1 mechanism may operate for substitution in the less reactiveand Gold has emphasised that, at high acidities, there arestill some difficulties over the mechanism illustrated ab0ve.7~Eaborn and Taylor 75 have determined the partial rate factors for thedisplacement of tritium by hydrogen a t the aromatic carbon atoms oftoluene, t-butylbenzene, biphenyl, naphthalene, and the halogenobenzenes.Their results indicate that the activating effects pf methyl and t-butyl groupsin the para-position can lie in either the inductive or the hyperconjugativeorder, depending on the medium,75a and that the variation in the ortho : pararatios in different media should be attributed to the reactivity of the reagent,not to different degrees of steric hindrance at the ~rtho-position.~~Other studies on acid-catalysed hydrogen-isotope exchange concern thereactions of substituted azulenes 7 and the effect of stannic chloride on reac-tions involving carboxylic acids.76Partial rate factors have been measured for the base-catalysed hydrogen-isotope reactions of dimethylaniline with amide ions in liquid ammonia.77In these and related reactions the most important factor appears to be theinductive effect of the substituent in modifying the acidity of the C-Hb0nds.7~ Base-catalysed hydrogen-isotope exchange in azulene appears tooccur most easily at the 1- and the 3-position 78-a somewhat unexpectedresult, since these are positions of high electron density.These reactions, togetherwith hydrogen-isotope exchange, have been recently reviewed.79 Kuivilaand Nahabedian have given further details of the protodeboronation of suchcompounds as p-methoxyphenylboronic acid ;loa, 80 the results support theearlier conclusion 81 that the reaction occurs by a slow proton transfer toReplacement of other substituents by hydrogen.the aromatic ring, followed by fission of the C-B bond.However, thedependence of the reaction rate on acidity, together with other evidence,indicates that two paths are involved, namely, directA-XE2 reaction at low acidities, and prior attachmentof a bisulphate ion to the boron (structure 11) atEaborn and his co-workers 82p 83 have studied theeffect of substituents in the aryl group on the rate ofcleavage of aryl-metal compounds by aqueous perchloric acid containingsome methanol or ethanol. These reactions are represented (in a slightlysimplified form) by the equation:where X = Ge, Sn, or Pb, and R = Me, Et, or cyclohexyl. For the ger-manium compounds,82a a logarithmic plot of the rate coefficient against thea+-values for the substituents is linear, but this is not true for the relatedcompounds of tin 83 and lead.8Zb The rates of cleavage of the tin and leadcompounds give linear plots when the function o + 0*4(0+ - G) is used asthe o-value of the substituent (cf.ref. 6Oa). This deviation from the con-ventional o-values for electrophilic substitution indicates that cleavage ofthe tin and lead compounds makes a relatively slight demand on the electron-donating properties of the substituents. Eaborn and Pande 82b point outthat these reactions clearly proceed by electrophilic attack at the carbonatom of the metal-aryl bond and thus the relative ease of cleavage is nota measure of the relative electronegativity of the organic fragment.Protodeiodination of p-iodoaniline loa in dilute aqueous acids appearsto involve slow addition of a proton to the aromatic ring, followed by a fastreaction in which the I+ ion is lost.The reaction is not catalysed by iodideions and the rate follows the h, acidity function.Olah, Kuhn, and Flood 84 have obtained some very interest-ing results on the nitration of the alkylbenzenes and the halogenobenzenesby nitronium tetrafluoroborate in tetrahydrothiophen dioxide. Under theseconditions the relative reactivities of the alkylbenzenes are surprisinglysimilar, and toluene is only 1.6 times more reactive than benzene, comparedwith the usual factor of about 25.However, this lack of discriminationbetween different molecules is not attended by a lack of discriminationbetween the individual positions of substitution ; thus the proportion ofmeta-substitution in toluene (2.8%) is about normal. These results make itvery difficult to believe that the carbon atoms are competing individuallyfor the nitronium ion, particularly since the partial rate factor for meta-substitution in toluene is far below unity (0.14). It is therefore suggested s4that the formation of a n-complex between the aromatic rings and thenitronium ion is rate-determining, and in support of this it is pointed outthat the rates of nitration can be correlated with the relative stability ofNitration.162 ORGANIC CHEMISTRYn-complexes.The orientation of substitution is considered to be deter-mined by the position of the nitronium ion in the n-cornple~,~~ but theresults do not seem to exclude the possibility that t,he rate-determining stepis followed by a second, product-determining step in which the orientationis determined only by the relative stability of the a-complexes a t the differentcarbon atoms.The results for the halogenobenzenes are in general agreement with thosegiven above, although the differences from normal nitration procedure areless marked. Deuteration of benzene, toluene, and fluorobenzene has beenobserved 84 to increase the rate of nitration under the same conditions; fordeuteration and nitration a t the para-position in fluorobenzene, E,/k, = 1.22.The work of Norman and his co-workers 85-87 has considerably increasedthe information on the orientation and partial rate factors of aromaticnitration and has clarified some of the factors determining ortho :pararatios.They have also confirmed that the rates of para-nitration of tolueneand t-butylbenzene lie in the inductive order.88Nitration of methyl 2-phenylethyl ether is of particular interest becausethe orientation varies with the conditions ;85a the amount of ortho-substitu-tion is 2S*9y0 with a mixture of nitric acid and sulphuric acid, and 66%with acetyl nitrate in acetonitrile. The greater amount of ortho-substitutionunder the latter conditions is attributed to the action of dinitrogen pent-oxide in forming the oxonium salt (12); this is considered to undergo theintramolecular rearrangement (12+ 13).The same authors 85b have shown that the high ortho :para ratiosobserved in the nitration of benzene derivatives with --M substituents (e.g.,nitrobenzene) are paralleled in chlorination by positive chlorine ; this sup-ports the view g9 that an electronic effect on the aromatic ring is involved,rather than rearrangement from a side chain. Other recent papers concernthe nzeta-directing effect of the P+O group in triphenylphosphine oxideand the possible formation of the mixed anhydride NO,*O*SO,H in mixturesof nitric acid and sulphuric a ~ i d . ~ l There is some evidence that nitroniumacetate can act as an acetoxylating reagent;92 the reaction of o-xylenewith nitric acid in acetic anhydride gives about 50% of 3,4-xylyl acetate.Kupinskaya and Shilov93 have shown that the rate ofchlorination of anisole by hypochlorous acid can be determined by a slow,acid-catalysed reaction between the acid and dissolved silver chloride (about10 -5w) ; this reaction presumably forms molecular chlorine which rapidlychlorinates the anisole.The zero-order reaction reported by de la Mare,Ketley, and Vernon has been interpreted in the same way, and the r61eof halogen cations (e.g., C1+) a t low acidities has been recon~idered.~~ How-ever, a t these very low concentrations, silver chloride is probably completelyionised into silver and chloride ions, and so the reaction studied by Kupin-skaya and Shilov 93 probably involves chloride ions and hypochlorous acid.This is unlikely to apply to the zero-order reactions studied by de la Mareet ~ 1 .~ ~ since the rate was not very sensitive to the silver ion concentration.Aromatic chlorination by t-butyl hypochlorite does not appear to be afree-radical reaction; the ortho : para ratios are consistent with reactionthrough either positive chlorine or molecular chlorine, depending on thecondition^.^^ Other recent papers have concerned the effects of variouscatalysts (CF,*CO,H ; ZnCl, ; IBr) on halogenation in organic solvents ;the influence of solvent composition on the chlorination of toluene andt-butylbenzene has also been studied. 98 The chlorina-tion of biphenyl by molecular chlorine in acetic acidgives about 14% of an adduct containing four chlorineatoms:99 the greater part of this product is believedto have the stereochemistry shown in structure (14) ;the extensive formation of the adduct suggests thatsuch additions are more important than is generally realised.Although many aryloxide ions appear to react with molecular brominein aqueous media a t about the encounter rate, this is not true for the 2,4-di-nitrophenoxide ion or for anisole derivatives.100 Partial rate factors havebeen measured for the bromination of biphenyl and naphthalene by molecularbromine in acetic acid.lO1 The acidity dependence of the ortho : para ratioin the bromination of biphenyl by hypobromous acid in aqueous acetic acidhas been explained lo2 in terms of two brominating agents, BrOH,+ andBrOAc; the former appears to give a +o : p ratio of about 0.59, and thelatt,er one of about 0.17.Nucleophilic Aromatic Substitution.-A new view of the S,l transitionstate in the decomposition of arenediazoninm ions has been put forward byHalogenation.Taft.103 The accelerating effect of meta-substituents being greater thanthat expected from the Hammett equation, he suggests that the transitionstate has a high degree of radical-ion character in that during the heterolysisa n-electron of the aromatic ring moves “ with concerted uncoupling ” intothe sp2-orbital involved in the C-N bond.This is considered to give riseto a triplet aryl cation (15) which derives some stabilisation from the inter-action of the lone n-electron with the substituent.lo4Some very large solvent effects in the bimolecular mechanism of nucleo-philic aromatic substitution have been considered to arise from differencesin relative solvation of the attacking anions,lo5 and a general account ofthese solvation effects is given on p. 171. The relative reaction rates ofsubstituted phenoxide ions with 1 -chloro-2,4-dinitrobenzene suggest Io6 thatthe transition state is very similar to the completely localised Whelandstructure; for the substituent effects are similar to those on the acidity ofphenols.lo6 Other recent kinetic studies on the displacement of chlorideions from 1 -chloro-2,4-dinitrobenzene concern the reaction withamines 1079 108 and with methoxide ions.logBunnett and Buncell10 have studied the rate of displacement of themethoxyl group from the azonaphthyl ether (16) in aqueous acid.Fromthe dependence of the reaction rate on the activity of water (after allowancefor the protonation of the azo-group) they conclude that the slow stepinvolves proton-transfer to the incipient methoxide ion (17). It is a littledisturbing that the medium-dependence for the reaction of the analogousphenyl ether is sufficiently different to suggest nucleophilic attack by wateron the carbon atom of the methyl group. If the implied difference in thepoint of bond fission is borne out by isotopic studies, these results will bea notable success for Bunnett’s treatment of medium effects in strongacids (cf.p. 154).J. F. Bunnett and E. Buncel, J. Amer. Chem. SOC., 1961, 83, 1117RIDD: THEORETICAL ORGANIC CHEMISTRY 165The nucleophilic displacement of chloride ions from cyanuric chloride(2,4,6-trichloro-l,3,5-triazine) by aniline in benzene has been studied byBitter and Zollinger.111 Both acids and bases catalyse the reaction andthere is evidence that 2-pyridone, but not 4-pyridone, can act as a bifunc-tional catalyst.The reaction of 1,3$-trinitrobenzene with bases has sometimes beenconsidered to involve proton-loss,ll2 but the work of Miller and Wynne-Jones 113 makes it more probable that electron-transfer is involved. How-ever, the problem is complicated by the fact that, in pyridine solution, theresulting charge-transfer complex is largely dissociated into ions ;I1 3b refer-ence is made to an earlier suggestion me that the pyridine cation (C,H,N+)can be stabilised by the formation of a three-electron N-N bond with anotherpyridine molecule.By using an acetone-ether solvent at low temperatures,Allen, Brook, and Caldin have measured 114 the rate of formation of a charge-transfer complex between 1,3,5-trinitrobenzene and a dimer of diethyl-amine. The ‘reaction of the trinitrobenzene with hydroxide ions is complexand light-sensitive.Homolytic Aromatic Substitution.-A redetermination of the relativerates of phenylation of benzene and nitrobenzene 116 has necessitated minorchanges in the partial rate factors for the phenylation of many substitutedbenzenes. 116 Previous work on the arylation of benzotrichloride requiresmore serious correction.The report that only me&-substitution is observedin the reaction with p-nitrophenyl radicals 117 is incorrect: the productsare 118 o- > 3%, m- - 64%, p- - 32%. The reaction with phenyl radicalsgives less meta-substitution (o- 12%, m- asyo, p - 39y0), in accord with presentviews on the polarity of substituted phenyl radi~a1s.l~~ Other work con-cerns the nucleophilicity of methyl and p-methylphenyl radicals 119 rela-tive to phenyl radicals; and arylation of naphthalene has been studiedfurther.121 There is some evidence for steric effects in the reaction ofo-chlorophenyl radicals with o-dichlorobenzene.122Other aspects of free-radical chemistry are not being considered in thisyear’s Report, but the following references may be useful.Homolyticoxidation has been reviewed by Waters,123 and reactions of alkyl compoundsby Kerr and Trotman-Dickenson.l2* Part of the latter review overlapsthe discussion of hydrogen abstraction from aliphatic compounds byTedder.125 Bartlett and his co-workers have published a series of paperson the concerted fission of two or more bonds in the decomposition of peroxy-compounds.126 A review of free-radical chemistry by Williams is mainlyconcerned with substitution.127 Developments in the physical chemistryof free radicals are described in the report of the International Symposiuma t Uppsala.12sHeteroaromatic Compounds.-Heats of combustion are now availablefor a number of a z o l e ~ , ~ ~ ~ but their interpretation in terms of resonanceenergies is complicated by uncertainties in the energy of the classical struc-tures ; nevertheless, it appears probable that the resonance stabilisation isappreciable.Microwave studies of isotopically substituted thiophens havegiven considerable information on the molecular structure ; 130 the double-bond character of the C-S bond in thiophen is considered to be much greaterthan that of the C-0 bonds in furan.130At low acidities, the conjugate acid of quinazoline has been recognisedfor some time to have the abnormal structure (18), resulting from the addi-tion of a water molecule. The first effect of increasing the acidity has nowH OH(‘8) (‘9) (20)been shown 131 to be dehydration, so that the normal cation (19) is the pre-dominant form in sulphuric acid at Ho -4.3.At still higher acidities thedi-cation (20) becomes the main component. However, from considerationsof relative reactivity the abnormal cation may still determine the orienta-tion of electrophilic substitution, even in strongly acidic media.132 Otherstudies of acid-base equilibria concern pyrazine l33 and substitutedimidazoles. 134By isotopic labelling with 15N, D. J. Brown has proved 135 that the re-arrangement of the methyl group, shown in structures (21) and (22), isaccompanied by a shift of the indicated nitrogen atom; it appears that ringopening occurs, followed by rotation about one C-N bond and ring closure.Eaborn and Sperry 136 have measured the acid-catalysed displacement oftrimethylsilyl groups at different positions in several heteroaromatic com-pounds, including dibenzofuran and dibenzothiophen. For dibenzofuran,the partial rate factors are lower than for nitration but show that there isa much greater preference for substitution para to the oxygen atom.Thisdifference in the orientational pattern of protodesilyla,tion and nitrationmakes it probable that neither reaction follows the order of n-electrondensities in the isolated dibenzofuran molecule. The orientation of carb-oxymethylation of dibenzofuran has also been measured ;I3' 1 -substitutionpredominates, and the reaction appears to be homolytic.Other recent work includes the unexpectedly easy chlorination of 2,5-di-methylpyra~ine,~~~ and the bromination of pyridine l-oxide both by positivebromine at high acidities 139 and by what appears to be an addition-elimina-tion mechanism.140 Dewar and his co-workers have given further considera-tion to the reactivity 141 and aromaticity 142 of " borazarenes "; compoundswith a boron atom between two ring nitrogen atoms do not appear to havesignificant aromatic stability.143 The diazapentalene (23) has been pre-pared 144; its basic properties are very slight.J.H. R.Part IIElectrophilic Substitution at a Saturated Carbon Atom.-Metallic leavinggroups. This subject has not previously been reviewed. Three main typesof reaction have been studied: (i) halogenation, (ii) acidolysis, and (iii) ex-change. The reacting group R retains its configuration in all cases wherethe reactions are bimolecular in mechanism, in contrast to nucleophilicsubstitution where inversion is more general.Possible mechanisms, and the problems involved in the study of theexchange reactions, are set out by Charman, Hughes, and 1ngold.l" Thethree possible exchange reactions are one-alkyl (iiia), two-alkyl (iiib), andthree-alkyl (iiic) :(i) R-HgX + X, + RX + HgX,(ii) R-HgR + HX f RH + RHgX(iiia) R-HgX + HgX, + R-HgX + HgX,(iiib) RzHg + HgX, + ZRHgX(iiic) R,Hg + RHgX + RHgX + R,Hg136C. Eaborn and J.A. Sperry, J., 1961, 4921.13' P. L. Southwick, M. W. Munsell, and E. A. Bartkus, J . Amer. Chem. SOC., 1961,138A. Hirschberg and P. E. Spoerri, J . Org. Chem., 1961, 26, 2356; H. Gainer, M.139 H.C. von der Plas, H. J. den Hertog, M. van h e r s , and B. Haase, Tetrahedron140 M. Hamana and M. Ya.mazaki, Chem. and Pharm. Bull. (Japan), 1961, 9, 414.141 M. J. S. Dewar and V. P. Kubba, J . Amer. Chem. SOC., 1961, 83, 1757.142M. J. S . Dewar and R. Dietz, Tetrahedron, 1961, 15, 26.143 S. S. Chissick, M. J. S. Dewar, and P. M. Maitlis, J . Amer. Chem. SOC., 1961, 85,144 W. Treibs, Naturwiss., 1961, 48, 130.H. B. Charman, E. D. Hughes, and C. K. Ingold, J., 1959, (a) 2523, (b) 2530.83, 1358.Kokorudz, and W. K. Langdon, J . Org. Chem., 1961, 26, 2360.Letters, 1961, 32.2708168 ORGANIC CHEMISTRYReaction (iiib) was the earliest studied because the products are different&om the reactants. Retention of configuration was first indicated by thework of Nesmeyanov et who used a displaced group with more than oneasymmetric centre, and this, together with the bimolecular character ofthe reaction, was confirmed by using di-( - )-s-butylmercury where themolecular dissymmetry is due to single asymmetric centres bound directlyto mercury.lb The SEl mechanism was thus excluded.The rate ofexchange increased as the ionicity of the salt increased, indicating the XE2rather than the SEi mechanism. Similar conclusions have been drawnmore recently from three-alkyl and uncatalysed one-alkyl exchange re-actions by the use of double labelling with 203Hg and (-)-s-butyl groups.This type of 8E2 mechanism in which the attacking and leaving groupsare on the same side of the reacting centre is supported for the one-alkylexchange by observations that neopentylmercury compounds react at asimilar rate to ethylmercury compounds.Reutov et al.interpret their results on the two- ti and three-alkyl 7exchange as involving a four-centre transition state (1). A similar four-centre transition state has been postulated by Dessy and Lee,8 but asthe exchange of ethylphenylmercury with mercuric halide involves equalamounts of cleavage of phenyl and ethyl groups9 they suggest that thetransition state must be symmetrical with respect to the two mercuryatoms (2). Other symmetrical transition states have been ruled O U ~ . ~ ~ ,CIThe proposed transition state is compatible with the obtuse angle betweencarbon-mercury bonds in ethylphenylmercury 9b and with the effect ofsubstituents in the phenyl ring, but the possibility of different mechanismsof attack at sp2- and sp3-carbon atoms has not yet been ruled out.Cat-alysis of the one-alkyl reaction by one or two anions has been attributed toeasy reaction by the 8,; mechanism.1°The XEl mechanism has also been demonstrated;11 the rate of the one-alkyl exchange between ethyl a-bromomercuri-a-phenylacetate and 203HgBr22A. N. Nesmeyanov, 0. A. Reutov, and S. S. Poddubnaya, Izvest. Akad. NaukH. B. Charman, E. D. Hughes, C. K. Ingold, and F. G. Thorpe, J., 1961, 1121.E. D. Hughes, C. K. Ingold, F. G. Thorpe, and H. C. Volger, J., 1961, 1133.0. A. Reutov, T. P. Karpov, E. V. Uglova, and V. A. Malysnov, Tetrahedron( a ) R. E. Dessy, Y. K. Lee, and J-Y.Kim, J . Amer. Chem. SOC., 1961,83,1163 ;lo H. B. Charman, E. D. Hughes, C. K. Ingold, and H. C. Volger, J., 1961, 1142.0. A. Reutov, W. I. Sokolov, and I. P. Reletskaya, Izvest. Akad. Naulc S.S.S.R.,S.S.S.R., Otdel. khim. Nauk, 1953, 649.6E. D. Hughes and H. C. Volger, J., 1961, 2359-* O . A. Reutov, Angew. Chem., 1960, 72, 198.*R. E. Dessy and Y. K. Lee, J . Amer. Chem. SOC., 1960, 82, 689.Letters, 1960, No. 16, 6.(b) H. Sawatsky and G. Wright, Canad. J . Chem., 1958, 36, 1555.Oldel. khirn. Nauk, 1961, 1217JOHNSON: THEORETICAL ORGABIC CHEMISTRY 169in 70% aqueous dioxan is independent of the mercuric bromide concentra-tion. The effect of substituents in the phenyl group is also consistent withthe unimolecular mechanism. Two-alkyl exchange does not occur betweenR,M and MBr, where M = Cd, Be, or Mg (R = Et or Ph) because thecorresponding compounds R-MBr do not exist .I 2 The disproportionation ofalkyltrimethylsilanes 13 in benzene in the presence of aluminium bromidehas been postulated as a displacement on carbon and nucleophilic attack onsilicon, also involving the X,i mechanism, with steric effects dominant incontrolling the rate.Retention of configuration and second-order kinetics are characteristicof acidolysis, though the demonstration of retention of configuration is lessclear-cut because of side reactions.14 Four-centre transition etates,15 andXE2 attack by the hydronium ion 16 in which C-H bond formation is rate-determining, have been proposed. Solvent isotope effects (k@, = 1.7 & 0.3and 1.0 for the acidolysis of cyclopropyl- and methyl-mercuric bromide,respectively) are considered to support the latter mechanism.In general,the rate increases from t-butyl to methyl and with increasing s-characterof the C-metal bond.17 The rate sequence Ph,Hg > Ph2Pb > Ph,Sn foracidolysis is manifested mainly in the activation energy. 0 bservations thatsome acidolyses, e.g., that of isopropyl- but not of cyclopropyl-mercuricbromide, are greatly accelerated by oxygen 18 may invalidate some of theearlier conclusions.The halogenation of a dialkylmercury is also bimolecular, with stereo-specific retention at the displaced carbon.lg In non-polar solvents the re-action involves free-radicals, but in polar solvents it is ionic.In some casesoxygen has little effect on the rate,lg but in others the rate is reducedS2*The fate of carbanions in solu-tion depends upon their structure, the nature of the leaving group, thesolvent, and the counter-ion. A carbanion capable of attaining a con-figuration with a plane of symmetry, e.g., (3; X = H,21 Et,22ay NMe2,23OMe 22b), generally tends to give a completely racemic product in dimethylsulphoxide, and one with partial retention of configuration in t-butylalcohol (or propanol), but there is net inversion in ethylene glycol. Theresults have been attributed to different amounts of asymmetric solvationand, by use of deuterated solvents,21 it was shown that the product is gener-ally formed by proton abstraction from the solvent.When the carbanion170 ORGANIC CHEMISTRYcontains an internal proton source 23 (3; X = OH or NH,), there is netretention in both t-butyl alcohol and ethylene glycol. The carbanions(3 and 4; X = CN ,*) with carbon as the leaving group are more susceptibleto racemisation, particularly in less acidic solvents, because of their ambi-dentate nature. The dependence of steric course on the counter-ion (NR,+or K+) is shown by the net retention of configuration for (3; X = CN) int-butyl alcohol with NR;, whereas only racemisation occurs with K+. Thecarbanions (3 and 4; X = CN, CO*NH, or C02Et), with hydrogen as the leav-ing are completely racemised in all solvents, the amount of deu-terium exchange in a deuterated solvent being equivalent to the amount ofracemisation.When the free carbanion might be expected to be non-planar,hydrogen exchange is much faster than racemisation 25a, and some reten-tion is found in all solvents. This has been explained for the compound (5)by assuming that asymmetry arises by overlap of empty sulphur d-orbitalswith either the lone pair in .sp3 hybridised, or the p-orbital in the rehybridised(sp2-p) carbanion. The latter type of overlap is less likely because of thelack of any through-conjugation effect when some a-sulphonyl-carbanionsare forced into this configuration.26a Cram et 1 3 1 . ~ ~ ~ observed small isotopeeffects in the racemisation and deuterium exchange of compound (5), butunder other conditions 25b no isotope effects were observed in the racemisa-tion.&Orbital overlap has also been suggested as the main factor contri-buting to the faster hydrogen exchange of tri(thioethoxy)methane than oftriethoxymet hane. 6b.The rate of deuterium exchange in CF,*CD(Hal), is much greater thanthe rate of elimination of DF 27a and it has been suggested that the tri-fluoromethyl group is equal to, or better than, the fluorine atom in facilitatingformation of a carbanion. Factors that favour the carbanion (relative tothe concerted E-2) mechanism of elimination have been discussed,27b andthe generalisation that the absence of a kinetic isotope effect implies thathydrogen is not transferred in the rate-determining step has been criti-~ised.27~ The rates of base-catalysed tritium exchange of phenyltritio-acetylene 28 have been measured in H,O and D,O; the isotope effect(EoD-/kOR- = 1-34) is consistent with hydroxide ion’s acting as a base ornucleophile. Calculations show that the reactions of the phenylacetyleneanion with water and with H,O+ have E, M los and E, rn loll 1.mole-lJOHNSON: THEORETICAL ORGANIC CHEMISTRY 171sec.-1, respectively. The pK,'s of a number of cyanocarbon compounds 29are remarkably low; e.g., cyanoform has pK, -5.13 in perchloric acid and-5-00 in sulphuric acid. Carbanions have also been postulated as possibleintermediates in the base-catalysed elimination of nitrous acid from benzylnitrate,3OU in the solvolysis of nitrostyreneY3Ob and in the Hofmann elimina-tion of ethylene from triethylsulphonium halides 30c by triphenylmethyl-sodium.The complete stereospecificity of rearrange-ment of ally1 ethers to cis-propenyl ethers has been ascribed to the partialbonding of the metal ion to both ends of the intermediate carbanion in thetransition state.31, A similar transition state, but with specific participa-tion of the solvent, has also been postulated.31b Benzyl migration in 2,2,3-triphenylpropyl-lithium 32a is faster at 0" than phenyl migration in 2,2,2-triphenylethyl-lithi~m,~~~ and phenyl migration is faster than p-tolylmigration in 2-phenyl-2-p-tolylpropyl-lithium.32C This is in accord witha carbanion intermediate for which it has been calculated that the ion withthe half-migrated phenyl group has lower energy than the free unbridgedcarbanion.Z,%Diphenylpropylmagnesium does not rearrange, the cor-responding lithium compound rearranges only above 0", and the potassiumcompound can be prepared only in the rearranged form.32c The isomerisa-tion of lithiobenzyl s-butyl ether in aprotic solvents to the lithium salt ofcc-s-butylbenzyl alcohol proceeds with some retention of configuration, theamount of retention decreasing with increasing solvation of the cation.33Dehydrochlorination of 2-chloro-1 , l-diphenylethylene in di-n-butyl ether 34involves phenyl migration in the free carbanion or a concerted carbanion-migration mechanism. A concerted cyclic mechanism may also be involvedin the exchange of alkyl and aryl groups between triaryl-sulphonium or-telluronium ions and alkyl l i t h i ~ m s , ~ ~ " and in the reaction between ethyl-lithium and benzyl chloride for which a lithium kinetic isotope effect hasbeen 0bserved.35~Nucleophilicity and Basicity of Anions. -Much attention has beenpaid to the fact that many reactions are greatly accelerated in dipolaraprotic solvents or by traces of dipolar aprotic solvents in other solvents.For example, the rate enhancement in ion-dipole reactions is up tolo5 for bimolecular nucleophilic aromatic substitution 36 and up to 107for bimolecular nucleophilic aliphatic substitution 37, 38 and carbanion172 ORGANIC CHEMISTRYformation.24b Since conductivity studies 39 show that most electrolytesare completely dissociated a t low concentration in dipolar aprotic solvents,studies of these reactions have shed light on the concepts of nucleophilicityand basicity of ions.Rate enhancement for an ion-dipole reaction on goingfrom a protic to a pure aprotic solvent is generally due to a large decreasein the solvation of anions (particularly small anions), coupled with smallerchanges in the solvation of cations and of large, negatively charged, polaris-able transition states. 36Cavell has shown that the marked decrease in the rate of reaction betweeniodide ion and butyl bromide 40a or iodide in acetone caused by theaddition of small amounts of water cannot be accounted for in terms ofchanges in dielectric constant alone. Evidence has been presented for anequilibrium of the type (iv) (R = H, Me) which decreases the concentrationof the reactive anions in'solution.The addition of small amounts of methanolto acetonitrile 41 causes only negligible changes in dielectric constant, butstill there is a large decrease in the rate of halogen exchange; this decreasewas used in calculating an association constant (K,) for reaction (iv). Thevalues of K, which were obtained when phenols were added in place ofmethanol were proportional to the integrated intensity of the O-H stretchingfrequencies of the phenols.41The effect of solvent change from pure water, methanol, or ethanol topure dimethyl sulphoxide on the alkaline hydrolysis or alcoholysis of methyliodide 38 has been studied. For water, log k2 ( E , = second-order rate con-stant) is an almost linear function of the mole fraction (%) of dimethyl sulph-oxide.This is due to an initial linear decrease in activation energy down to x 0-5, followed by a levelling-off, coupled with an initial decrease in log Adown to x w 0.5, followed by a subsequent increase. Although dimethylsulphoxide 42a and dimethylformamide 42b can form compounds with methyliodide and dimethyl sulphate, respectively, the trimethylsulphoxidiumsalt 42a is not an intermediate in this reaction. The addition of 10 moles yoof dimethyl sulphoxide to methanol 24a causes a much larger increase(18-fold) than the addition of any but the final 10 moles yo of dimethylsulphoxide (>35-fold) in the rate of carbanion formation from (+)-a-methyl-j3-phenylpropionitrile and methoxide ion. The effect of smallamounts of dimethyl sulphoxide has been ascribed to specific solvation ofthe transition state, whereas a t very high concentration dimethyl sulphoxidecompetes effectively with methoxide ion for the remaining methanol, thusleaving methoxide ions relatively unsolvated and reactive.The rate in-crease in the reaction of butyl bromide with carbani0ns,~3 on addition offrom 5% to 95% of dimethylformamide to the benzene solvent, is a linearunction of the dimethylformamide concentration and has been ascribed tosolvation of the cation associated with the carbanion.These changes in the solvation of anions are such that aprotic solventstend to level, and protic solvents tend to differentiate, the nucleophilictendencies of halide and halogenoid ions,37 whereas, conversely, aproticsolvents tend to differentiate, and protic solvents to level, the carbonbasicity 44 and hydrogen basicity aQa of such ions.Rates of solvolysis arescarcely changed on going to dipolar aprotic s01vents,3~, 45 but concomitantfirst- and second-order exchange of chloride ion with diphenylmethylchloride in dimethylformamide has been reported. 48 The reaction betweenpyridine and butyl bromide 47 is not appreciably influenced by change toa dipolar aprotic solvent,, suggesting that dipole-dipole reactions may notbe influenced as much as ion-dipole reactions; however, this may be a for-tuitous cancellation of effects because small amounts of dimethyl sulphoxideaccelerate the reaction between allylamine and 1 -chloro-2,4-dinitrobenzene 48in 2-phenylethanol .Of importance to the interpretation of rates of SN3 reactions in aqueous-a'lcoholic solution are explanations 49 of rate changes observed when smallamounts of water are added to alcohol solvents.With methanol there isan initial increase, with ethanol (except in the presence of the stronglynucleophilic, but weakly basic, thiophenoxide ions) there is a decrease, inrate. The difference in behaviour has been ascribed to the surprisinglyhigh concentration of the less reactive hydroxide ion in ethanol containingsmall amounts of water, whereas corresponding methanol solutions containmainly methoxide ion.Carbonium Ions.-Non-chsical carbonium ions. Acetolysis of cis-bicyclo[3,1 ,O]hexan-3-y1 toluene-p-sulphonate (6) is subject to a special salteffect and anchimeric ac~eleration,~~" and the 3-deuterated toluene-p-sul-phonate gives the cis-acetate in which the deuterium is equally distributedamongst positions 1, 3, and 5;50b these facts are uniquely consistent withthe intervention of the trishomocyclopropenyl cation (7).Acetolysis ofthe trans-isomer involves little deuterium redistribution, special salt effectsor anchimeric acceleration, indicating little interconversion between classicaland non-classical ions. The structure and implications of homoaromaticand homoallylic carbonium ions have been discussed. 5~ The exact structureof the homoallylic carbonium ion derived from cholesteryl compounds isdescribed as (8) rather than (9) because the same products are obtainedfrom cholest er y 1 and 3p - h y dr ox y met hyl-4-norc holest - 5 -ene toluene -p - sul-phonate (10) on acet~lysis.The products of solvolysis of alliylmercurysalts are characteristic of normal solvolytic reactions.59 The reaction inacetic acid is slow, but on addition of perchloric acid, an instantaneous reac-tion (v) occurs, which is then followed by a slower reaction yielding mercury,perchloric acid, and solvolysis products.The product composition is inde-pendent of the anion; e.g., cyclohexylmercury salts give 89.5 & 1.3% ofolefin and 10-5 &- 1.3% of a cyclohexyl derivative. The most probablemechanism involves scheme (via, b).(v)(via)(vib)GeneraE solvolytic reactions.R*HgX + HCLO, -+ RHgCIO, + HXR-HgX + RHg+ + X-R.Hg+ -F HgO + R+ + ProductsSlowThe very large difference (+ 17.5 kcal./mole) in free energy of activationbetween methyl and t-butyl salts, 59b when compared with the previoushighest value (<S kcal./mole), implies that the reaction involves a transi-tion state which is highly charged in relation to the initial state.The formation of +4y0 of methane on treatment of methyl bromide ina hydrocarbon solvent with aluminium bromide has been ascribed to theformation of the methyl cation which abstracts a hydride ion from thesolvent.60 The spectrum of a number of allylic compounds in sulphuricacid has been reported to be due to allylic carbonium ions.61 The fadingof solutions of the triphenylmethyl ions in, for example, acetic anhydrideor nitromethane containing small amounts of ether has been ascribed tothe formation of a 1 : 1 complex between the ether and the carboniumion.62a I n chloroform, the tri(methoxypheny1)methyl ion is fairly stable,but the colour of the tri(to1uene-p-sulphonylpheny1)methyl and triphenyl-methyl ions fades much more rapidly, particularly in " wet " ch1oroform.6zbThe first-order reaction of 2-chloroethyltrimethylsilane to give ethyleneis dependent upon the ionising power, but not the nucleophilicity, of thesolvent. 63a Intervention of the trimethylsilyl cation has been postulated,and the suggestion made that such ions may be as accessible as carbo-nium ions, but that alternative reaction paths may be more favoured withsilicon compounds. Deamination of trimethylsilylmethylamine 63b involves,not the trimethylsilylmethyl cation, but loss of the elements of diazo-methane, probably by nucleophilic attack on silicon.A study of the stereo-chemistry of a number of reactions of alkylsilyl halides, alcohols, ethers,and esters 63c in solvents of low ionising power, shows that " good " leavinggroups such as chloro or acyloxy lead to predominant inversion, but withpoorer " leaving groups other stereochemical paths are available. Re-actions involving nitrosation, diazotisation and deamination have beenreviewed.64The upper limit of exchange of [35S]thiocyanate ion with diphenyl-methyl thiocyanate 65a is less than one-third of the rate of isomerisationto the isothiocyanate, indicating the intervention of ion-pairs, even in aceto-nitrile as solvent. Ion-pairs are also indicated in the solvolysis of diphenyl-methyl p-nitro[ 180]benzoate 65b (where the rate of carboxyl- 1 8 0 scram-bling is three times the solvolysis rate) and in the chloride ion exchangewith an optically active diarylmethyl chloride 65c (where, even in the presenceof a highly dissociated inorganic chloride, the rate of racemisation exceedsthe rate of exchange). In the presence of mercuric chloride,66 the ratioof the rate of racemisation to the rate of exchange is reduced to 1-50 & 0-03,though both racemisation and exchange rates are greatly enhanced.Thissuggests that all exchange occurs by regeneration of RC1 from RfHgC1,-ion-pairs which have become racemic and have lost all distinction betweenthe three chlorine atoms.The solvolysis and rearrangement of propylbromide in the presence of mercuric salts in aqueous formic acid has alsobeen disc~ssed.~'Methyl 2-deoxy-~-glucopyranosides,~~~ like most alkyl glycosides, under-go acid-catalysed hydrolysis by the A- 1 mechanism with hexose-oxygenfission, but hydrolysis of t - butyl ,k?-D-glucopyranoside involves alkyl-oxygenfission. The observation of an O-isotope effect (k16/k18 = 1.03) in theacid-catalysed hydrolysis of methyl a-D-glucopyranoside and the predom-inant inversion on hydrolysis of phenyl 2,3,4,6- tetra- O-met hyl-P-D- gluco -pyranoside and of phenyl a- and p-D-glucopyranosides indicate that suchsolvolyses do not involve ring opening. X-Phenyl 2 , 3,4,6- te tra-O-met hyl-P-D-thioghcopyranoside resists acid-catalysed methanolysis.Acid-catalysedhydrolysis of a series of phenyl a-~-glycosides,~~" unlike that of the cor-responding ~ - ~ - g ~ y c o s i d e s , ~ ~ ~ is unaffected by substituents in the phenylgroup. This has been attributed to easier elimination of phenol via an anti-periplanar transition state [scheme (vii)] which is accessible from the a-con-figuration only. Comparison of relative rates for the p-isomer and thecorresponding methyl glycosides suggests that this may not be a generalreaction. The rates of acid-catalysed hydrolysis of glucose and mannoseare decreased by both primary and secondary deuterium isotope effects.70The secondary effect is due almost entirely to deuterium in position 1 andis almost unaffected by deuterium in other positions. In the acid-catalysedanomerisation of 1,3,4,6-tet;ra-O-acetyl-2-deoxy-~-glucopyranoside the rateof l-acetoxy-exchange is greater than the rate of inversion (k,/ki = 1-8-3.7)indicating an X,l type of mechanism.The fission of arylalkyl ethers inconcentrated sulphuric acid is a normal A-1 reaction, but alkyl ethersundergo attack by sulphur trioxide on the oxonium salt 72 to give theintermediate [R1R20.S0,H] + which slowly decomposes ; the extent of forma-tion of this intermediate is critically dependent on the solvent concentration.Solvolysis of adamantan- 1 -yl derivatives (1 9) 73a is easier than mightbe expected, being only 1000 times slower than that of t-butyl, but lo5and 1011 times faster than that of bicyclo[2,2,2]octan-l-yl and bicyclo-[ 2,2,2]heptan-l-y1 derivatives, respectively.The difference from t-butyl isascribed to angle strain in a somewhat flattened, but not planar, transitionstate, and there is no evidence to suggest that inhibition of bridgeheadhyperconjugation can alter the rate significantly. The acetolysis of adam-antan-2-yl toluene-p-sulphonate (20) 73b is 15 times slower than that ofcyclohexyl toluene-p-sulphonate, but lo6 times faster than that of 7-norbornyltoluene-p-sulphonate. The formation of oxazolines 74a from 2-benzamido-4-t- butylcyclohexyl and from 2-benzamidocyclohexylmethyl sulphonate, whichrequire the anti-periplanar conformation in the transition state, has beenused to show that the anchimeric driving force in the reaction must be .greater than 5.5 kcal./mole, quite sufficient to allow all or part of the reac-tion to proceed through the boat conformation where necessary.Theassisted pyrolysis of the all-equatorial 2-hydroxy-NNN-trimethyl-5-t-butylcyclohexylammonium hydroxide 74b also proceeds through the boatconformation.The ratio AC*/AS$ in aqueous acetone may be diagnostic of the SN1mechanism 76a in cases where other methods fail. Thus in SNl reactionsthe ratio has a value >2-77, whereas much smaller values occur for 8,Zand mixed-mechanism reactions. The use of this criterion of mechanism178 ORGANIC CHEMISTRYhas also been discussed by Robertson and Sc0tt.~6~ The volume change ofactivation in the reaction between ethyl iodide and tripropylamine inmethanol ( - A V = 24 c.c./mole) 77a is much less than the overall volumechange during reaction (-AV = 56-6 c.c./mole); this result is difficult toreconcile with the view that the transition state resembles the solvatedproduct.The corresponding value for the reaction between methyl iodideand N-ethyl-N-methylaniline is 20 c . ~ . / m o l e , ~ ~ ~ and that for the reversereaction is -45 c.c./mole. The difference between these values is inreasonable agreement with the value (-AV, = 55.8 c.c./mole) for theoverall volume change a t 25". Discrepancies with previous work havebeen put down to the variation of A V with pressure.Carbenes.-This subject has been reviewed.78 The kinetics of thethermal decomposition of diazodiphenylmethane have been st~died.79~3Precise measurements on the decomposition of 2,2'-azodi-(a-mefhylpropio-nitrile) in several solvents show that the rate and activation parameters varyconsiderably with the solvent and calculations indicate that plots of A&'$against AH2 may well be linear because of systematic errors in their computa-tion.Reaction of photochemically produced methylene with allenes andbutadiene involves competitive addition to double bonds and insertionin C-H bonds ; the excited cyclopropane derivatives thereby produced areunstable unless deactivited by collision. The spectroscopic states of methyl-ene in solution and in the gas phase have been discussed.81 Methylenereacts with the carbon-halogen bond in simple alkyl halides,82 the reac-tivity order being primary > secondary > tertiary.The reactions arecompetitive with reaction a t the C-H bond and, for primary and secondaryhalides, the intermediate (21) has been postulated. Dichlorocarbene (fromchloroform and base) has been inserted by cleavage of mercury-halogenbonds,83 to give trichloromethylmercury compounds, as in (viii) :Rearrangements occur with carbenes derived from neopentyl and relatedhalides. Labelling with deuterium was used to show that methyl migrationand intramolecular C-H insertion can occur in neopentylcarbene. 84a,Thermally produced carbene from 2-methyl-2-phenyl-2-diazopropane 85undergoes phenyl migration, methyl migration, and C-H insertion in theratio 10 : 1 : 8.3, which is a much greater proportion of methyl migrationthan is observed with the corresponding carbonium ion.Isobutene isformed from an n-butyl or isobutyl halide and a strong base by predominanta-elimination to give the intermediate carbene,84cs 86 except in the case ofisobutyl iodide ; 84' no a-elimination occurs with s-butyl chloride or isobutylmethyl ether or sulphide.86 Cyclic carbenes derived from five- or six-membered rings give lOOyo of 0lefin,~7 but those from larger rings givemixtures of olefins and products derived by 1,3-, lJ5-, and 1,6-transannularalk ylation.There is kinetic evidence for the occurrence of dibromocarbene on brom-ination of tribromomethane by hypobromite ion,88 and for occurrence ofp-nitrophenylcarbene. 89 Methylene and mono- and di-methoxycarbonyl-carbene react with increasing discrimination with C-H bonds (in the ordertertiary > secondary > primary C-H), owing to the smaller reactivity ofthe substituted carbenes ; polar structures in the transition state areIsoelectronic nitrogen analogues of carbenes, i.e., R-N:, have beenpostulated as intermediates in the photochemical decomposition of alkyl,gla~vinyl,91c and acyl 91d azides.Consideration of the volume change of activa-tion in the Curtius rearrangement 92 and the kinetic form of the alkalinedecomposition of N-chloroacetanilide g3 are also consistent with acyl- andaryl-azenes, respectively. However, spectrophotometric studies on thephotolysis of methyl azide gave no indication of the presence of methylazene,only for that of a ~ i n i d i n e .~ ~Carbonyl and Related ReactiollS.-Conformation. Studies of the rela-tion between reaction rates and conformation continue. Acid-catalysedhydrolyses of methyl cyclohexane-mono- and -di-carboxylates and of methyl4-t-butylcyclohexanecarboxylates have been studied in detail 95a and theresults compared with those of the corresponding alkaline hydrolysis.g5bNo firm conclusions could be drawn from the rates of reaction about theimplicated. ..conformations of the trans-ly2-mono- and di-carboxylate, but they areprobably diequatorial, because, contrary to previous belief, the tr~ns-1~2-diacid and its monoanion are diequatorial. 96 The conformational equili-brium constant for the ethoxycarbonyl group has been estimated from theequilibration of ethyl cis- and trans-4-t-butylcyclohexanecarboxylate 97(AF - 1.2 kcal./mole), and the alkaline hydrolysis of ethyl cis-4-methyl-cyclohexanecarboxylate (AF - 1.0 to - l.2).97u These values are supportedby the equilibration of ethyl cyclohexane- 1,3-dicarboxylate 97b.and by acomparison of the rates of hydrolysis of ethyl cis- and trans-4-t-butylcyclo-hexanecarboxylate g70 (AF -1.O), but the latter agreement may be for-tuitous in view of several cases where a cyclohexane derivative reacts fasterthan the all-equatorial trans-4-t-butylcyclohexane derivative.95a, b , 98 Thecorresponding free-energy difference for the carboxyl group, calculated fromacid dissociation constants, is slightly larger [AF =' - 1 ~ 7 9 ~ ~ (corr., - 1-4 97(7,-l.6,99b -1.6 kcal./mole 99cJ.An 8 - 9-fold acceleration hasbeen demonstrated for alkaline hydrolysis of some alicyclic acetates at 25"where hydroxyl groups are on carbon atoms adjacent to the acetoxylgroup.100 Much greater accelerations have been observed at 78" by intro-duction of cis- and trans-hydroxyl groups adjacent to the acetoxyl group ofcyclopentyl acetate.lol The rate differences are markedly affected by tem-perature.The acceleration in the case of the trans-diol monoacetate (22)rules out previous suggestions that hydrogen bonding of the hydroxyl groupto the ether-oxygen atoms of the acetoxyl group in the transition state isresponsible for the acceleration, and indicates that hydrogen bonding tothe carbonyl oxygen in the transition state (23) and/or a microscopic mediumeffect are responsible, Facilitation of alkaline hydrolysis of methoxy-carbonyl groups by vicinal hydroxyl groups in some indole alkaloids has alsoIntramolecular facilitation of hydrolysis.Types I-V specific polysaccharides of Pasteurella psezdotuberculosiscontain a number of different 3,6-dideoxyaldohexoses comprising 3,6-dideoxy-D-xyb- (abequose), -D-arabino- (tyvelose), -L-arabino- (ascarylose),and -D-ribo-hexose ( p a r a t ~ s e ) .~ ~Acid degradation of the antibiotic chalcomycin yields chalcose, a 4,6-dideoxy-3-O-methylaldohexose. 52Several deoxy-sugars, including di-, tri-, and tetra-saccharides, havebeen detected in the hydrolysed glycosides from the nodules of Raphiommeburkei.53Cyclic derivatives. The importance of hydrogen- bonding on acetalformation is discussed in a paper in which the methylene groups of thetri-0-meth ylene acetal of D -g&ycero-D -glum- heptitol (p- sedoheptitol) areshown to be in the 1,3 : 2,4 : 5,7-p0sitions.~4Phenylboronic acid reacts with methyl OI-D-glucopyranoside to give the 4,6-cyclic ester, con-p h 1 3 < ~ ~ . o & verted by more of the acid into the 2,3-(diphenyl0 pyroboronate) (4). Similarly, methyl CC-D-man-nopyranoside is converted by an excess of theacid into the 2,3 : 4,6-die~ter.~~ These estergroups are readily removed by water or alcohols.Unlike p-D-glucopyranose 2,3,4,6-tetra-acetate 1-nitrate, the pentanitrate does not easily undergo anomeriza-tion, presumably because the 2-nitrate group, unlike the acetate, does notparticipate in the displacement.As expected, treatment of the penta-nitrate with methanol gives methyl a-D-glucopyranoside tetranitrate, butunfortunately the reactivity of this compound is too low for the method tobe of value for preparation of disaccharides. However, condensing 3,4,6-tri-O-acety~-$-D-glucopyranosy~ chloride 2-nitrate with p-D-glucopyranose1,2,3,4-tetra-acetate gives a good yield of the isomaltose derivative, togetherwith a small proportion of genti~biose.~~The ester group of a number of aldose 1-(2,4,6-trirnethylbenzoates) hasbeen displaced by treatment with methanol containing methanesulphonicIn a typical example, p-D-glucopyranose 1 -(2,4,6-trimethylbenzoate)is converted into methyl a-D-glucopyranoside.Study of anomerization and exchange reactions at position 1 of the2-deoxy-~-g~ucopyranose tetra-actetates 58 where no neighbouring groupeffect is possible has shown that the reactions proceed by-the XNl mechan-ism.59 In such reactions in acetic acid, acetic anhydride, and sulphuricacid there is a pronounced acceleration due to an isotope effect when theacids contain deuterium.6oTreatment of 2-acetamido-2-deoxy-~-ribose or D-arabinose with aqueousammonia gives an equilibrium mixture of the two containing twice as muchof the arabinose compound. The amount of each epimer in the mixturedepends on the relative stabilities of the chair conformations Gf the pyranosering.61 Prolonged treatment of D-glucosamine with aqueous ammonialeads to the production of 2 -met h y 1- 6 -D -arabino- tetrahydroxybut yl- , 2 -methyl-5 -D -arabino-tetrah ydroxybutyl, 3- D -erythro- trihydroxypropyl- , and2,5- bis- (~-arab~no-tetrahydroxybutyl) -pyrazine.Several anomeric pairs of N-aryglycosylamines have been prepared bydeacetylation of their acetates by sodium in methanol, in which mutarota-tion is arrested.63 N-Arylaldosylamines undergo true transglycosylationin ethanol containing hydrogen chloride and another arylamine.64When a sugar o-chloro- or o-iodo-phenylosazone is heated with aqueouscopper sulphate the phenylosotriazole is obtained, dehalogenation occur-ring.65 Osotriazoles are stoicheiometrically oxidized by ceric salts, to give2-phenyl-l,2,3,triazole-4-carboxylic acid.66N-Beizzyloxycarbonyl-amino-acids condense readily with sugarsin pyridine in the presence of dicyclohexylcarbodi-imide, esterificationinvolving mainly the primary alcoholCrystalline arsenites that are readily hydrolysed have been preparedfrom alditols and arsenic trioxide.68In the nitration of D-fructose the product obtained depends on the acidityof the esterifying solution.It has now been found that use of nitroniumsulphate gives a compound, C,H,,07, with pyruvaldehyde joined by anacetal-type linkage to an anhydro-D-fructose. 69N-Alkyl- and N-aryl-carbamates are readily obtained by treating sugarsand derivatives with isocyanates. 70Treatment of D-ghCOSe in cold concentrated sulphuric acid with phos-phorus oxychloride is claimed to give excellent yields of D -glucose 6-phosphate(as the barium salt) which is believed to exist in the acyclic form.71 Thephosphate groups of a number of partially substituted myoinositol phos-,phates have been shown to undergo migration in acid solutions.72 Attemptsto prepare phosphate esters of sugars by treating deoxy-halogeno-derivativeswith silver phosphate 7 3 or silver diphenyl phosphate 74 sometimes lead toanhydro-sugars. The preparation is described of 5,6-, 3,6-, and 3,5-cyclichydrogen phosphates of D-glucose. 75D-Glucose 6-sulphate, isolated as the crystalline potassium salt, is pre-pared by treating D-glucose with pyridine-sulphuric anhydride in dimethyl-formamide 76 or with chlorosulphonic acid in cold concentrated sulphuricacid.77 Direct esterification is also found to occur mainly at c(6) in D-galaC-tose, but by using suitably substituted derivatives other monosulphates ofD-glucose and D-galaCtOSe have been prepared.78 Oxidation of sugar sul-phates with sodium periodate is complex but gives valuable information forcharacterizing unknown esters. 79 Acid hydrolysis of the methyl glycosidemonosulphates shows that the sulphate group stabilizes the glycosidic linkand that the 6-sulphate is more effective than the 3-sulphate. The parentsugar is the only one isolated, showing that no inversion of configurationoccurs. These experiments show that acid hydrolysis of sulphated polysac-charides should give some sulphated mono- and oligo-saccharides.80 Reduc-tion of sugar sulphates with lithium aluminium hydride leads to the parentsugar only, with no trace of deoxy-sugar.81 Solutions of hydrazine are onlypartially successful for removing sulphate groups.82Amino-sugars.D-Gulosamine is obtained from D-xylose by successivereaction with nitromethane, methanolic ammonia, and hydrochloric acid.83A general method by which all 2-amino-2-deoxy-~-aldohexoses have beenmade involves treatment of the D-pentose with hydrogen cyanide and9-aminofluorene, followed by removal of the fluorenyl substituent by cata-lytic hydrogenation. Methyl 2-ace tamido-4,6 -0-benzylidene-2 -deoxy-a- D -idopyranoside 3-methanesulphonate is converted by sodium acetate into the2 -amino-2-deoxy-~-talose derivative, and the 3-amino-%deoxy-~ -gulosederivative is obtained similarly from the D-idoside.86 Oxidative degrada-tion of the diethyl dithioacetal of 3-acetamido-3-deoxy-~-altrose gives2-acetamido-2-deoxy-~-ribose.~~ Crystalline 5-acetamido-5-deoxy-~-xyZo-hexulose is made by the oxidative action of Acetobucter suboxydum on2-acetamido-2-deoxy-~-glucitol.~~ A definitive synthesis of muramic acidis described.89 The structure of neosamine C, 2,6-diamino-2,6-dideoxy-~-glucose, obtained from the antibiotic complex, zygomycin A, has beenconfirmed by synthesis.g0Mycosamine is shown by synthesis to be 3-amino-3,6-dideoxy-~-man-nose,91 and mycaminose to be 3,6-dideoxy-3-dimethylamino-~-glucose. 92Two new arnino-sugars from an antigenic polysaccharide of Pneumococcushave been tentatively identified as 2-amino-2,6-dideoxy-talose and -L-galactose.93A method for purifying amino-sugars involves the preparation andhydrogenolysis of a suitable SchWs base.94 Amino-sugars are convertedinto the N-acyl derivative by treatment with the acid in the presence ofdicyclohexylcarbodi-imide. 95When a mixture of D-glucosamine hydrochloride and D-mannose isheated on paper a small quantity of N-mannosyl-D-glucosamine is formed. 96Under more drastic conditions disaccharides are produced ; 6-O-mannosyl-~-glucosamine has been isolated.Polyamides , including a tetrahydroxy-Nylon 6,10, have been preparedby the interfacial reaction of sebacoyl dichloride and suitably substitutedlY6-diamino- 1 -6-dideoxyhexitols. 98The presence of the acetamido-group of3-acetamido-3-deoxy-~-allose diethyl dithioacetal favours the formation of2-acetamido-~-ribose by oxidation with peroxypropionic acid.The pentoseis not obtained directly by similar oxidation of D-altrose diethyl dithio-a ~ e t a l . ~ ~Controlled oxidation of a number of sugar dithioacetals gives monosul-phoxides; these are stable to alkali, but they are readily converted by dilutemineral acid into the parent sugar and a dialkyl disulphide and by methanolichydrogen chloride into methyl furanosides and pyranosides. Also obtainedwere a number of disulphoxides that are stable to acid at room temperaturebut readily degraded to the next lower aldose by dilute ammonia.loOTetra-0-acetyl-D-ribofuranosyl bromide is obtained by treating alkyl1 -deoxy-1 -thio-a-D-ribofuranosides with acetic anhydride followed bybromine.lo1 Treatment of analogous compounds with mercuric acetate orsilver benzoate results in the replacement of the alkylthio- by the acyloxy-radical.1°2 The action of Raney nickel on aldose dithioacetals gives the1-deoxyalditols ; partial desulphurization has been found to be a reasonablemethod for making 1 -deoxy-1 -thioethylalditols. 1°3Sugars with a sulphur atom in the ring have been reported for the firsttime. Successive treatments of 1,2-O-isopropy~idene-~-xylofuranose 5-folu-ene-psulphonate with sodium thiocyanate and sodium sulphide, or sodiumthiosulphate and potassium borohydride, lo4 orpotassium thiolacetate and sodium in methanol lo5yield crystalline 5 -deox y - 1,2 - O-isopropylidene- 5 -mercapto-D-xylose, hydrolysis of which gives 1 4 0D-xylothiapyranose (5).The pyranose ring isextremely stable and mutarotation is slow evenwhen catalysed by ammonia.Reagents: 1, (a) CS,-NEt,, (b) MeI, (c) Me*SO,Cl. 2, Boiling C,H,N.3, Al-Hg. 4, HC1 (to remove CHPh:), then HgCl,. 5 , H,S.In another sequence the amino-group is formed by reducing theazido-residue introduced by treating a toluene-p-sulphonate with sodiumazide, and the thiol group is obtained by debenzylating the benzylthio-derivative produced by opening an epoxide ring with sodium benzyl sulphide.Methyl 2-amino-4,6 - 0- benzylidene- 2,3 -dideox y - 3-mer capto-/3-~ -alloside hasbeen made from methyl 2-amino-4,6-0-benzylidene-2-deoxy-/3-~-glucoside inrather a similar manner.Di- and Oligo-saccharides.-Columns containing a mixture of carbon andaluminium oxide have been successfully used for separating mono-, di-, andloSL.D. Hall, L. Hough, and R. A. Pritchard, J., 1961, 1537.C. Jamieson and R. K. Brown, Canad. J . Chern., 1961, 39, 1765.lo* For a review see D. R. Kalkwarf, Nucleonics, 1960, 18 (No. 5), 76.log L. Goodman and J. E. Christensen, J . Amer. Chem. SOC., 1961, 83, 3823.J. E. Christensen and L. Goodman, J . Amer. Chem. SOC., 1961, 83, 3827.l l l W . Meyer zu Reckendorf and W. A. Bonner, PTOC. Chem. SOC., 1961, 429HO'NEYMAN : CARBOHYDRATES 345tri-saccharides. In this way p-gentiobiose has been isolated from the mix-ture obtained by treating D-glucose with emulsin.l12Sophorose, which has been found to have a remarkable stimulatingeffect on the cellulase production of a strain of Trichoderma viride,l13 hasbeen synthesized by a simple method,l14 which modifies the conditionsdescribed earlier : 115 methyl 4,6-O-benzylidene-a-~-glucoside reacts withacetobromoglucose to give a sophorose derivative from which the free sugaris isolated by acetolysis followed by deacetylation.Crystalline or-ko jibiose (2- O-a-D-glucopyranosyl-a-D -glucopyranose) hasbeen obtained by the action of lactase on a branched trisaccharide result-ing from the action of Leuconostoc mesenteroides on a mixture of sucroseand lactose.l16The 1,6-glycosidic link in polysaccharides is the most stable to acidhydrolysis, but the least stable to acetolysis.This has enabled kojibioseand nigerose to be isolated 11' from the acetolysis of the dextran, known tobe unusually rich in 1,2 linkages,lls from Leuconostoc mesenteroides NRRLB-1299. From another strain, B-421, nigerose is isolated in particularlygood yield.117Treatment of a mixture of maltose and D-xylose with a transglycosylasefrom Penicillium lilacinum gives 3-O-~-~-glucopyranosyl-~-xylose.~~~Sodium hypochlorite degrades maltose and lactose to crystalline 3-0-a-~-glucopyranosyl- and 3-O-~-~-galactopyranosy1-~-D-arabinose, respectively, inyields of about 35y0.120Leucrose (5-O-a-~-glucopyranosyl-~-fructopyranose) is the main sugarisolated from the product formed by dextran-producing cultures of Strepto-coccus bovis acting on sucrose.121Several novel disaccharides have been obtained by treating chondroitinsulphate A, B, or D with a chondroitinase preparation from Proteus vulgaris.A and B both give the A49 5-~-g~ucuronido-~-acety~-~-ga~actosamine4-(hydrogen sulphate) (€9, whereas Dgives the isomeric 6-( hydrogen sulphate).HC*OHF H ----Another except that disaccharide it is a di(hydrogen from D is sulphate) similar H O .; g HC.0I-I 1 O . d H liJD-galactose part and the other probablyH0,S.O. CHICHI1co CH,*OH Iwith one sulphate residue on c(6) of theon or C(3) of the uronic acid part.A similar but distinct disaccharide di-sulphate is also obtained from B.122 COlH (8,Crystalline stachyose tetrahydrate has been prepared from the tubers112V.D. Stefanovid, J . Chromatog., 1961, 5, 453.113M. Mandels and E. T. Reese, Biochem. Biophys. Res. Comm., 1959, 1, 338.114B. Coxon and H. G. Fletcher, jun., J. Org. Chem., 1961, 26, 2892.115 K. Freudenberg, H. Toepffer, and C. C. Andersen, Ber., 1928, 61, 1750.l l s F . Yamauchi and K. Aso, Nature, 1961, 189, 753.117 K. Matsuda, H. Watanabe, K. Fujimoto, and K. Aso, Nature, 1961, 191, 278.118 T. A. Scott, N. N. Hellman, and F. R. Senti, J . Amer. Chem. SOC., 1957, 79, 1178.119 S. A. Barker, M. Stacey, and D. B. E. Stroud, Nature, 1961, 189, 138.laoR. L. Whistler and K. Yagi, J. Org. Chem., 1961, 26, 1050.121E. J. Bourne, D. H. Hutson, and H. Weigel, Biochem. J., 1961, 79, 549.122S. Suzuki, J . Biol. Chem., 1960, 235, 3580346 ORGANIC CHEMISTRYof the Japanese artichoke (Stuchys sieboldii, Stachys tuberi,fera).l23 A largenumber of oligosaccharides containing D-galactose and sucrose have beenisolated from the roots of Cucubulus b u ~ c i f e r .~ ~ ~A monosodio-sucrose has been obtained free from ammonia,125 anda crystalline sucrose monoacetate has been prepared by treating sucrose withacetic anhydride in pyridine.126 Hydrogenolysis of sucrose in ethanol ordioxan at 180 gives 2,6-anhydro-~-~-fructofuranose (2,5-anhydrO-B-D-hctopyranose), a new type of anhydro-ketose in which the 2,6-ring is inthe boat form and is very sensitive to acid.I27When maltose in ethanol is treated with piperidine, acetic acid, and tri-ethylamine the Amadori rearrangement product, 1 -deoxy- 1 -piperidino-maltulose, is obtained. With lactose, however, the reaction goes furtherand U-D-galactosylisomaltitol is produced.Hydrolysis or pyrolysis of thisgives isomaltitol, which may be 2-acetyl-3-hydroxyfuran but is still beinginvestigated. 128Exposure of polysaccharides to y-radiationleads to degradation. Dextran is more rapidly attacked if oxygen is presentbut the primary reaction under any conditions appears to be the formationof free radi~a1s.l~~Further separations have been made by using gel filtration throughSephadex, a cross-linked dextran. Fractionation is according to molecularsize and a number of dextrans of low molecular weight have been examinedin this way.130Reaction with iodine in calcium chloride solution has been suggested forprecipitating linear polysaccharides from mixtures containing also branchedmolecules.By this method ivory-nut mannan is shown to be composed oflinear molecules only. 131The Weerman reaction has been applied to oxidized polysaccharides 132and shown to confirm the structural information obtained by the Barrydegradation. 133The molecular weights, determined by the light-scattering method, ofthe polysaccharides made by heating lzvoglucosan in the presence of acidrange from 2600 to 310,000. About 55% of the glucosidic linkages involveC(s), 35% are at C(2) or C(4), and 10% at C(3) This is in reasonable agree-ment with the known reactivities of the different positions.134 Polymeri-zation of 1,6-anhydro-~-~-galactose also yields branched-chain polysaccha-rides but with a rather lower proportion (43%) of the glycosidic linkagesinvolving C(6).135 Branched molecules have also been obtained by heatingPolysaccharides.-General.D-glucose with phosphoric anhydride or sulphuric acid,136 and from a varietyof sugars, including disaccharides, by heating them in dimethyl sulphoxidecontaining acid. l 3 7A xylanase-free transglucosylase from Penicillium Zilcccinum has been usedto make a glucoxylan by transferring glucosyl units from maltose to esparto-grass xylan.138Cellulose.When a solution of a cellulose triacetate in nitromethane wassupercooled crystallization occurred slowly. The resulting crystals, whichwere visible under the microscope, were square and of lamellar structure,the chain molecules being normal to the planes of the lamellae. Deacetyla-tion was achieved without affecting the shape of the crystals or the orienta-tion of the resulting cellulose I1 molecules.139A comparative study of the methods available for obtaining the homo-logous series of oligosaccharides from cellulose has shown that best yieldsresult from direct acid hydrolysis.In addition to all members up to cello-hexaose a small amount of celloheptaose was obtained, together with indi-cations for the first time of the presence of the octaose and n0na0se.l~~Etherification of cellulose with ethylene oxide to give O-hydroxyethyl-celluloses leads to progressive modification of the structure of the fibres inthe manner typical of a topochemical r e a ~ t i 0 n .l ~ ~ Random substitution ofthe products occurs with toluene-p- sulphonyl chloride. 1 *2Treatment of acetylated triphenylmethyl ethers of cellulose with hydro-gen bromide in anhydrous acetic acid at 0" gives cellulose acetates having anunusually high proportion (87 %) of the free hydroxyl groups attached toc(6). By acetylating a partially hydrolysed cellulose acetate with aceticanhydride a t room temperature the product was almost completely substi-tuted a t c(6). A range of cellulose acetates differing only in the positionsof the substituents is now available.143Several classes of dye are known which react with cellulose during dye-ing.* These include derivatives of dichloro- and monochloro-l,3,5-tri-a ~ i n e , l ~ ~ , lP5 of vinyl sulphone and the hydrogen sulphates of 2-hydroxyethyls u l p h o n e ~ , ~ ~ ~ and of chlor~pyrimidines.~~~ In mild alkali only one of thechlorine atoms of the dichloro-l,3,5-triazine derivatives reacts, whereasunder more drastic conditions both react to give a cross-linked cellulose136T.Nakamura, J . Chem. SOC. Japan, Ind. Chem. Sect., 1960, 63, 1769.la? F. Micheel, A. Bockmann, and W. Meckstroth, Makromol. Chem., 1961, 48, 1;F. Micheel and R. Puchta, ibid., p. 17; F. Micheel and D. Mempel, ibid., p. 24; F.Micheel and H. Alfes, ibid., p. 33.lseS. A. Barker, M. Stacey, and D. B. E. Stroud, J., 1961, 3995.la9R. St. J. Manley, Nature, 1961, 189, 390.140 G. L. Miller, J. Dean, and R. Blum, Arch. Biochem. Biophys., 1960, 91, 21.Ia1M. Oberlin and J.Quinchon, MakromoE. Chem., 1960, 41, 218.142 J. Quinchon, Bull. SOC. chim. France, 1960, 2071, 2073.143 W. R. D. Leigh, J . , 1961, 754.144 Imperial Chemical Industries Limited, B.P. 772,030, 774,925, 781,930.lQ5 Ciba Ltd., B.P.775,308, 780,591 ; Imperial Chemical Industries Limited, Belgian146 Farbwerke Hoechst A.-G., B.P. 733,471; German P. 953,103.14? Imperial Chemical Industries Limited, French P. 1,182,006; Bayer A.-G.,P. 543,071.Belgian P. 572,973.*For a review of the chemistry of reactive dyes see H. Zollinger, Angew. Chem.,1961, 73, 125348 ORGANIC CHEMISTRYderivative.14* The presence of a covalent link between cellulose and dyehas been shown by isolating a coloured D-glucose derivative from the prod-ucts obtained by the microbiological degradation of the dyed cellulose.149Many cross-linking agents for cellulose have been examined in attemptsto obtain cotton fabrics with resistance to creasing.The compounds whichreact in this way include 1,3-dichloropropanol, 150 derivatives of divinylsulphone,151 tris-aziridin-l-ylphosphine 0Xide,152 and di-epoxides.153Cellulose acetate crotonates have been cross-linked by treatment withamines, and the reactions of unsaturated esters in the presence of peroxideshave been studied. 15* Supporting investigations on D-glucose derivativesare described.155Still milder methods are being sought for isolatingstarch and its fractions without degradation. One method 156 depends onleaching starch with hot water in the absence of oxygen and is good on asmall scale, giving an amylose which has a weight-average molecularweight >1 x 106.This amylose is hydrolysed to the extent of 95% by/I-amylase. Unfortunately this method is difficult to use on a larger scale.157Another small-scale method employs prolonged contact at room tempera-ture with dimethyl sulphoxide, to give a solution from which both amyloseand amylopectin are precipitated with butanol. The precipitate is thenredissolved by heating it briefly in oxygen-free water at 70" and the amyloseis precipitated with butanol. After one recrystallization the amylose hasa weight-average molecular weight of 1.9 x lo6 and is attacked to the extentof more than 95% by p-amylase. The yield is essentially quantitative andthe chemical modification is negligible.Evidence is presented for believing that in amylose the D-glucose ringsexist in chair (Cl) and boat (3B) conformations in equilibrium.In theamylose-iodine complex the chair form predominates but the units ofretrograded amylose are mainly in the boat form.158The or-amylolysis of potato starch gives maltotetraose 63-phosphate 159as Limit dextrin. This structure is elucidated by a method depending onover-oxidation with sodium periodate.160 Although most of the phosphateof starches is attached to amylopectin it is possible that small amountspresent as ester groups on amylose may account for the incomplete hydro-Starch and gZycogen.149 T. L. Dawson, A. S. Fern, and C. Preston, J . SOC. Dyers and Coburists, 1960, 76,149 0.Stamm, H. Zollinger, H. Zahner, and E. Giiumann, HeZv. Chim. Acta, 1961,160 Fothergill and Harvey Ltd., B.P. 696,282; Deering Milliken Research Corp.,161G. C. Tesoro, P. Linden, and S. R. Sello, Teztile Res. J., 1961, 31, 283.163 G. L. Drake and J. D. Guthrie, Textile Res. J . , 1959, 29, 155.16s C. W. Schroeder and F. E. Condo, Textile Res. J., 1957, 27, 134; R. Steele, ibid.,164W. M. Corbett and J. E. McKay, J . SOC. Dyers and Colourists, 1961, 77, 543;W. M. Corbett, J., 1961, 2926; W. M. Corbett and J. E. McKay, ibid., p. 2930.210.44, 1123.B.P. 855,547.1961, 31, 257.J. E. McKay and W. Taylor, ibid., p. 547.166 G. A. Gilbert, Sturke, 1958, 10, 95.157P. J. Killion and J. F. Foster, J. Polymer Sci., 1960, 46, 65.158 J.Holl6, J. Szejtli, and M. T6th, Sturke, 1961, 13, 222.lasThe nomenclature is that of W. J. Whelan, Ann. Rev. Biochem., 1960, 29, 105.laoF. W. Parrish and W. J. Whelan, Biochem. J.: 1961, '49, 19PHONEPMAN : CARBOHYDRATES 349lysis of some amyloses by p-amylases. Potato and wheat amyloses weretreated with phosphatase in conjunction with ,&amylase without any changein the amount of hydrolysis; the small amount of phosphate in the amylosesmay be attached to the reducing end or may be present as a diester which isnot attacked by phosphatase.161Starches from commercial maize and from high-amylose maize have afraction amounting to 4-9% which has molecules intermediate in shapebetween amylose and amylopectin. This material is less highly branchedthan amylopectin, is stained blue by iodine, and absorbs iodine to theextent of 60 mg.per g.lS2 The amyloses from high-amylose maize starcheshave molecular weights and iodine affinities similar to those of ordinaryamyloses, but the amylopectins have molecules with longer outer branches.163Theseare the cyclic molecules containing from six to twelve glucose ~ n i t s . 1 ~ ~Some of them readily form crystalline inclusion complexes with aliphaticacids.Examination166 of the absorption spectra of the iodine complexes ofa number of different amylopectins and glycogens shows that for amylopec-tins the maximum absorption is at about 540 mp whereas for glycogens it isa t about 460 mp. This and other data have revealed that Floridean starchfrom the fronds of Dilsea edulis is an amylopectin rather than a glycogen.le7The aggregated complex formed in alkaline solution from amylopectinand cetylpyridinium chloride is pictured as being a matrix of negativelycharged amylopectin molecules cross-linked by positively charged cetyl-pyridinium micelles.16*Four different methods based on oxidation with sodium periodate forthe end-group assay of glycogens have been critically examined. 169 Onlyone 170 of them is as reliable as the use of potassium periodate, but anotherwhich allows over-oxidation to proceed and then involves extrapolation tozero-time is also acceptable. 171 Glycogen, isolated from animal tissue bymethods which avoid the use of alkali, had a higher molecular weight(100 x lo6) than that isolated by alkaline extraction (1-8 x lO6).172All the products obtained from polysaccharides by periodate oxidationare rapidly degraded by alkali, but those from starches may be convertedinto alkali-resistant methyl acetals.173 No reaction has been found thatconfers similar alkali-resistance on the oxycelluloses.174Seven different Schardinger dextrins have now been isolated.161W. Banks and C. T. Greenwood, Chem. and Ind., 1961, 21, 714.162R. L. Whistler and W. M. Doane, Cereal Chem., 1961, 38, 251.lG3E. M. Montgomery, K. R. SBXSOP, and F. R. Senti, Starke, 1961, 13, 215.1'54A. 0. Pulley and D. French, Biochem. Biophys. Rea. Comm., 1961, 5, 11.l'35H. Schlenk and D. M. Sand, J . Amer. Chem. Soc., 1961, 83, 2312.166 A. R. Archibald, I.D. Fleming, A. M. Liddle, D. J. Manners, G. A. Mercer, and16'C. T. Greenwood and J. Thomson, J., 1961, 1534.lB8 M. M. Fishman and I. Freud, J . Colloid Sci., 1961, 16, 392.leeD. J. Manners and A. Wright, J., 1961, 2681.170D. J. Manners and (in part) A. R. Archibald, J., 1957, 2205.171A. S. Perlin, J . Amer. Chern. SOC., 1954, 76, 4101.172 M. R. Stetten and H. M. Katzen, J . Amer. Chem. SOC., 1961, 83, 2912.1731. J. Goldstein and F. Smith, Chem. and Ind., 1961, 1081.I74 J, Honeyman and J. R. Holker, Textil-Randachaz, 1961, 16, 561.A. Wright, J . , 1961, 1183350 ORGANIC CHEMISTRYPolysaccharides from bacteria, fuwi, and a2p. Further informationabout the amino-sugars present in bacterial cell-walls has been published.175The extracellular polysaccharides from several species of agrobacteriahave been shown to be composed mainly of p-D-glucopyranose units with1 +2-linkages.The polysaccharides are difficult to methylate completely,especially at C(3).176The highly branched mannan from baker’s yeast gives, on acid hydrolysis,a homologous series of 1+ 6-linked or-D-mannopyranose oligosaccharides.~77Acetolysis affords adztionally the l+2-linked di~accharide.17~The fresh-water green alga, Nitella translucens, contains 4% of astarch-like polysaccharide which has been found to consist of amylose(12%) and an amylopectin having an average chain-length of 19 glucoseunits. 179The cell-wall of Hydrodictyon africanum Yaman consists mainly of an‘‘ or-cellulose,” built up from equimolecular amounts of D-glucose andD-mannose, and a hemicellulose which is also a glucomannan.180The alkali-soluble polysaccharides of Chlorellct ppyrenoidosa include onewhich has similarities to starch, another which is a branched p-linked galac-torhamnan containing also arabinose, xylose, mannose, and glucose, and athird which contains mainly galactose,.glucose, and rhamnose but also 20y0of an unknown sugar.181The water-soluble polysaccharides from Caulerpa $Ziformis harvested inNovember have been hydrolysed to arabinose, xylose, galactose, and man-nose and are essentially similar to those of C . racemosa and C. sertuZurioides.ls2Laminarin from the brown algz is composed mainly of 1+3-linkedD-glucopyranose units but a few are 1+6-linked. The molecule also con-tains D-mannitol and probably has one branch-point. Chrysolaminarinfrom diatoms is of a similar molecular weight and has similarly linked glucoseunits (although a somewhat higher proportion are 1+6-linked) but containsno mannitol.183Measurements of pH have confirmed that alginic acids isolated from dif-€erent sources differ in structure.184Agarose, an agar polysaccharide from Gelidium Amansii, is composedof 1+3-linked units of agarobiose, 4-O-~-~-galactopyranosyl-3,6-anhydro-~-galactose.l8~ In the case of porphyran from Porphyra umbilicalis there isstrong evidence that the 3,6-anhydro-~-galactose units are formed in Naturefrom L-galactose 6-~ulphate,18~ which has also been obtained by hydrolysis1 7 5 5. M. Ghuysen, Ind. Chim. belge, 1960, 25, 1077; M. R. J. Salton, Biochim.Biophys. Acta, 1960, 45, 364; M. R. J. Salton and J. M. Ghuysen, ibid., p. 355.1 7 6 P. A. J. Gorin, J. F. T. Spencer, and D. W. S. Westlake, Canad. J . Chem., 1961,39, 1067.17’s. Peat, W. J. Whelan, and T. E. Edwards, J., 1961, 29.1 7 8 s . Peat, J. R. Turvey, and D. Doyle, J., 1961, 3918.l 7 O D . M. W. Anderson and N. J. King, J., 1961, 2914.l S o D. H. Northcote, K. J. Goulding, and R. W. Horne, Biochem. J., 1960, 77, 603.lE21. M. Mackie and E. Percival, J., 1961, 3010.ls3A. Beattie, E. L. Hirst, and E. Percival, Biochem. J., 1961, 79, 531.ls4A. Haug, Acta Chem. Scand., 1961, 15, 950.lE5 C. Araki and 5. Hiram, Bull. Chem. SOC. Japan,, 1960, 33, 597.186D. A. Rees, Biochem. J., 1961, 78, 25P.S. A. Olaitan and D. H. Northcote, Bwchem. J., 1961, 81, 7PH O N E Y M A N : CARBOHYDRATES 35 1of the p01ysaccharide.l~~ Porphyran1879 and the agar of CerumiumboydeniiTwo polysaccharides from carrageenin differ in that one contains galac-tose 6-sulphate whereas the other, probably formed from the first, incor-porates 3,6 - anhydrogalact ose . OA water-soluble polysaccharide of Enteromorphu compressa contains ahigher proportion of rhamnose with ester sulphate groups attached.lglInfrared spectroscopy suggests that the sulphate groups are axial 192 andtherefore attached to C(2) of rhamnose.lglIsolichenin, a food reserve polysaccharide of Iceland moss, Cetrariccislandica, is shown by partial acid hydrolysis to be made up of equal amountjsof a-D-gIUCOpyI’anOSe units linked 1+3 and 1+4, probably without anybranching.193 It is, however, different from nigeran which has an alternat-ing sequence of 1 +3- and 1 +4-a-~-glucopyranose units. Lichenin fromthe same moss contains @-D-glucopyranose units of which 70% are 1+4-and 30% 1 +-3-linked. Degradations of lichenin with laminarinase prep-arations show that this enzyme attacks either a 1+3- or a 1-+4-linkage of,8-D-glucopyranose which is attached throughHemiceZZuZoses.-The use of esterification with phenyl isocyanate forblocking free hydroxyl groups in carbohydrate acetates has been developedand applied to a glucuronoxylan from birch. About 24% of the xylose unitsare acetylated at 12% at C(2), and 6% at both. Migration of thephenylcarbamate group can occur, however.lg5Essentially linear glucomannans have been obtained from the wood ofEastern white pine (Pinus strobus, L.) lg6 and of Ginkgo biloba, L.197In an arabinogalactan of the Western larch some of the galactopyranoseunits are hydrolysed at about the same rate as the arabinofuranose ones;there is no evidence for the presence of galactofuranose ~nits.1~8 Anarabogalactan from maple-tree sap has been shown by gas-liquid chromat-ography to contain about 5% of rhamnose.199Acid-hydrolysis of the hemicelldoses of the wood of Landes maritimepine gives a number of uronic acids related to mono-, di-, and tri-saccharides,including a novel one, 2 -0- (4-O-methyl-a-~ -glucuronopyranosyl) -~-lyxo-pyranose . 200A low-molecular-weight xylan from tamarack has a main chain of about16 D-xylopyranose units linked 1+3, with possibly one 1+4, 3 single unitcontain 6 - 0- methyl- D - galactose.to another such unit.branches of 4-O-methyl-~-glucuronic acid linked 1+2, and a branch of anL-arabinofuranose unit.201The weight-average molecular weights of a number of 4-O-methyl-glucuronoxylans of woods correspond with degrees of polymerizations of450-500 units.202 The structures of a number of such xylans have beendiscussed.203Many galactomannans have been isolated from legume seeds and now agalactan, containing minor amounts (8%) of mannose and arabinose, hasbeen obtained from Centrosemu plumuri. The links are mainly 1-+4 butabout 15% are 1+3.204The gum exuded by Fqara xanthoxyloides gives, on gradedhydrolysis, a 4-O-(4-0-methy~-a-~-g~ucuronosyl)-D-ga~ac~ose 205 which hasalso been obtained from the gum of myrrh. Gum asafoetida has a highlybranched molecule with a backbone of (mainly) 1+3-linked @-D-galacto-pyranose units with side chains of residues of L-arabinofuranose, D-galacto-pyranose, D-glUCUrOniC acid, and 4-O-methyl-~-glucuonic acid.206 Thegums of Khaya senegalensis include one with a main chain consisting largelyof 1+4-linked D-galacturonic acid and of 1 +2-linked L-rhamnopyranoseunits.207 The gum from Albixxia xygia (Macbride) is unique in containingboth D-glUCUrOniC acid and its 4-O-methyl ether.208MisceEluneous. D-Glucuronic acid is the uronic acid present in heparin.209D-Glucosamine is the only sugar in chitin.210Simultaneous dialysis and partial acid hydrolysis of mucopolysaccharidesproceed without appreciable N-deacetylation and give additional oligosac-charides. Much new structural information is being obtained by use ofthis technique.211Plunt gums.

ISSN:0365-6217    

DOI:10.1039/AR9615800136

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

t1. BIOSYNTHESIS OF FATTY ACIDSTHE elucidation of the mechanism of fatty-acid oxidation at the enzymelevel,l-4 and the demonstration of the reversibility of all the reactionsinvolved, led most biochemists to believe that the biosynthesis of fattyacids was accomplished by a reversal of the ,&oxidation cycle. This con-cept was suggested in 1953 by Lynen and Lynen and Ochoa and receivedwide acceptance, even though Gurin and his co-workers 6--8 had demon-strated significant differences between oxidation and synthesis.attempted to synthesize fattyacids by using highly purified enzymes of the ,&oxidation cycle, reducedbenzylviologen as the reductant, and [ l-14C]acetyl-CoA, they were ableto produce only butyryl-CoA in small quantities. This failure to synthesizelong-chain fatty acids was attributed to the tendency of the enzyme thio-lase 10, 11 to catalyse the condensation of two molecules of acetyl-CoA toform acetoacetyl-CoA rather than the condensation of acetyl-CoA with ahigher acyl-CoA.Langdon l2 then discovered, in soluble extracts of rat liver, an enzyme,TPNH crotonoyl-CoA reductase, which catalysed the reduction of crotonoyl-CoA to butyryl-CoA, This enzyme was also isolated from pig-liver mito-chondria by Seubert et aZ.,13 extensively purified, and shown to have a widesubstrate specificity ranging from crotonoyl-CoA to octadec-2-enoyl-CoA.These workers showed that this enzyme, along with three enzymes of theB-oxidation cycle (thiolase,lo, l1 #Lhydroxyacyldehydrogenase,ll, l4 andenoyl hydrase 15, la) and a continuous source of DPNH (ethanol + alcoholdehydrogenase) and of TPNH (glucose 6-phosphate -t glucose 6-phosphatedehydrogenase) was capable of synthesizing decanoyl-CoA and octanoyl-CoAfrom hexanoyl-CoA and [ 1- 14C]acetyl-CoA.Popjdk and his co-workers obtained similar results with an enzyme systemisolated from rabbit mammary tissue.Hele, Popj&k, and Lauryssens 1 7However, when Stansly and Beinertl D . E. Green, Biol. Rev., 1954, 29, 330.2F. Lynen and S. Ochoa, Biochim. Biophys. Acta, 1953, 12, 299.G. R. Drysdale and H. A. Lardy, J . Biol. Chem., 1953, 202, 119.4A. L. Lehninger and G. D. Greville, Biochim. Biophys. Acta, 1953, 12, 188.SF. Lynen, The Harvey Lectures (1952-3), Series XLVIII, Academic Press,? F .Dituri and S. Gurin, Arch. Biochem. Biophys., 1953, 43, 231.New York, p. 210.R. 0. Brady and S. Gurin, J . Biol. Chem., 1952, 199, 421.J. Van Baalen and S. Gurin, J . Biol. Chem., 1953, 205, 303.P. G. Stansly and H. Beinert, Biochinz. Biophys. Acta, 1953, 11, 600.loD. S. Goldman, J . Biol. Chem., 1954, 208, 345.l1 F. Lynen, L. Wessely, 0. Wieland, and L. Rueff, Angew. Chem., 1952, 64, 687.lrR. G. Langdon, J . Biol. Chem., 1957, 226, 615.l3 W. Seubert, G. Greull, and F. Lynen, Angew. Chem., 1957, 69, 359.l4 S. J. Wakil, D. E. Green, S. Mii, and H. R. Mahler, J . Biol. Chem., 1954, 207,lS S. J. Wakil and H. R. Mahler, J . Biol. Chem., 1954, 207, 125.l6 J. R. Stern, A. del Campillo, and I. Raw, J . Biol. Chem., 1956, 218, 971.17P. Hele, G.Popjhk, and J. Lauryssens, Biochem. J . , 1957, 65, 348.631.354 BIOLOGICAL CHEMISTRYreported that this system catalysed the synthesis of even-numbered fattyacids of chain length C,-C,, from acetate although short-chain fattyacids, with crotonic acid as the major component, were the main products.CoASH, ATP, and DPN were required, but not TPN. Evidence wasobtained that p-keto-, p-hydroxy-, and ap-unsaturated acids up to c8 wereintermediates, by their isolation as hydroxamates. The activated formsof these intermediates were CoA derivatives. l8 However, since crotonicacid was the major product of synthesis, it was clear that this system lackedan enzyme capable of reducing ap-unsaturated fatty acids. Lachance,PopjAk, and de Waard19 showed that such an enzyme was present inmicrosomes (in contrast to its mitochondrial origin, reported by Seubertet aZ.13).Addition of microsomes to the soluble mammary-enzyme systemin the presence of [14C]acetate, CoASH, ATP, DPNH, and TPNH increasedten-fold the amount of butyric acid formed, and also increased the amountsof hexanoic and octanoic acid.Wakil, McLain, and Warshaw 2* reported recently that intact mito-chondria from pigeon, rat, or beef livers, when incubated anzerobically with[ 14C]acetyl-CoA, TPNH, DPNH, and ATP, produced long-chain fatty acids.The reaction was completely dependent upon ATP, and both DPNH andTPNH were required for optimal activity. The addition of hydrogen car-bonate ion did not affect the synthesis, although malonyl-CoA was incor-porated into fatty acids in the presence of ATP.However, since malonyl-CoA is known to be decarboxylated to acetyl-CoA by a mitochondrialenzyme,21 it is likely that this accounts for the utilization of malonyl-CoA.The addition of unlabelled acetate did not reduce incorporation of [ l%]acetyl-CoA into fatty acids, which suggests that the requirement of ATP does notreflect resynthesis of acetyl-CoA from acetate and CoASH by the aceto-thiokinase 22 reaction. The fatty acids synthesized by this system werestearic (40%), palmitic (20%), myristic (20%), and lauric (20%). Stearicacid, synthesized from [ l-14C]acetyl-CoA by this system, was isolated anddecarboxylated by the Schmidt reaction. The specific activity (c.p.m. perpatom of carbon) of the liberated carbon dioxide was twice that of stearicacid.This indicated that the stearic acid had been built up by elongationof a pre-existing short-chain fatty acid by successive addition of acetyl-CoA;this system contrasts with the malonyl-CoA system which carries out a truesynthesis de novo.Similar results had been obtained earlier in less well-dehed enzymesystems. Zabin,23 for instance, found that the 14C content of the carboxyl-carbon atom of stearic acid synthesized by liver slices from [l-l%]acetatewas higher than that of the other carbon atoms. In contrast, palmitic acidproduced simultaneously had a uniform distribution of 14C throughout themolecule.l*A. de Waard and G. PopjAk, Biochem. J., 1958, 68, 61..20 S.J. Wakil, L. W. McLain, jun., and J. B. Warshaw, J . Biol. Chem., 1960, 235,21 H. I. Nakada, J. B. Wolfe, and A. N. Wick, J . Biol. Chem., 1957, 226, 145.2 3 1 . Zabin, J . Biol. Chem., 1951, 189, 355.J. P. Lachance, G. PopjBk, and A. de Waard, Biochem, J., 1958, 68, 7 ~ .PC31.Hele, J . Biol. Chem., 1954, 206, 671MERCER: BIOSYNTHESIS O F FATTY ACIDS 355Wakil et aZ.20 also observed that incubation of stearoyl-CoA or oleoyl-CoA with [ 1 -14C]acetyl-CoAY TPNH, DPNH, and mitochondria underanaerobic conditions resulted in the production of fatty acids tentativelyidentified as C,, acids.Soluble enzyme preparations of mitochondria, obtained by extractingacetone-dried powders of mitochondria with phosphate buffer, readily in-corporated [ 14CIacetyl-CoA into long-chain fatty acids when incubated inthe presence of ATP, DPHN, and TPNH.It was found that dialysis ofthe soluble mitochondrial-enzyme preparation, followed by treatment withcharcoal, drastically reduced its activity. Activity could be restored bythe addition of a boiled enzyme preparation. Reactivation could also beaccomplished by the addition of fatty acids of intermediate chain length(e.g., C,, C,,) along with pyridoxal phosphate (pyridoxamine phosphatewas almost as effective). When octanoyl-CoA was added in order to restoreactivity, a C,, fatty acid was isolated which contained SOY0 of the [ 14C]acetyl-CoA incorporated into the total fatty acids synthesized. When a C,, fattyacid was added, a C,, fatty acid was the main product, and so on.Wakilinterprets this as indicating that the mitochondrial enzyme system causeselongation of fatty acids by addition of acetyl-CoA. The requirement ofthis system for ATP was eliminated when fatty acyl-CoA derivatives wereused, indicating that ATP is required for formation of acyl-CoA derivativesof endogenous fatty acids. The r61e of pyridoxal.phosphate in the mito-chondrial system has not been defined as yet. However, its participationin the process may go a considerable way to explaining the well-establishedconnexions between vitamin B, deficiency and deficiency in essential fattyacids. In 1936 Birch and Gyorgy24 observed that vitamin B,-deficientrats had symptoms of acrodynia similar to those of rats deficient in fattya ~ i d s , ~ ~ - ~ ~ and that unsaturated fatty acids had a sparing effect on vitaminB,.Later it was shown that the acrodynia caused by vitamin B, deficiencycould be cured by dosage with linoleic or arachidonic acid,Z4, 29 and Shermanet observed an increase in arachidonic acid synthesis in rats dosedwith pyridoxine. Wakil and his co-workers 2o suggest that the most likelyway in which pyridoxal phosphate functions in the fatty-acid elongationmechanism is as the prosthetic group of an enzyme which catalyses thecondensation of acetyl-CoA with the fatty acyl-CoA acceptor. This avoidsthe participation of thiolase in the condensation. Thiolase has two dis-advantages from the condensation viewpoint ; it maintains an equilibriumgreatly in favour of degradation (the equilibrium constant of the conden-sation is 1-6 x mole/l.at pH 7.0) and it tends to promote condensationof two molecules of acetyl-CoA rather than condensation of acetyl-CoA witha higher fatty acyl-CoA.It is postulated that the mitochondrial system requires DPNH for re-duction of the condensation product (p-oxo-acyl-CoA) to the correspondingz4T. W. Birch and P. Gyorgy, Biochew~ J . , 1936, 30, 304.26G. 0. Burr and M. M. Burr, J . Biol. Chem., 1929, 82, 345.26G. 0. Burr and M. M. Burr, J . Biol. Chem., 1930, 86, 587.27 G. 0. Burr, M. M. Burr, and E. S. Miller, J . Biol. Chem., 1932, 97, 1.28 G. 0. Burr, Fed. Proc., 1942, 1, 224.29 H. Sherman, L. M. Compling, and R. S. Harris, Fed. Proc., 1950, 9, 371356 BIOLOGICAL CHEMISTRYB-hydroxy-acyl-CoA, and TPNH for reduction of the a#?-unsaturatedacyl-CoA to the corresponding saturated derivative.Wakil et al.visualize the overall mechanism for elongation of fattyacids by liver mitochondria, taking palmitoyl-CoA as an example, as shownin Scheme 1.Condensing enzyme(pyridoxaiphosphate ?)R*CO*SCoA + CH,*CO*SCoA - R*CO*CH,*CO-SCoA + CoASHpalmitoyl-CoA(1 ) p- 0x0s tear o yl -CoA8- Hydroxyacyl- CoAdehydrogenase l4R*CO*CHZ*CO.SCoA + DPNH +- H+ ->RCH( OH) *CH,CO*SCoA,9-Hydroxystearoyl-CoAEnoyi hydraseR*CH( OH)*CH,.CO*SCoA + R*CH=CH*CO*SCoA +Octadec - 2 -enoyl -CoA+DPN+ (2)H2O ( 3 )cx,B-Unsaturatedacyl-CoA lS. 1*reductaseR*CH=CH*CO.SCoA + TPJSH + H+,-+R*CH,*CH,-CO*SCoA + TPN (4 )Stearoyl-CoASCHEME 1.Fam Acid Smthesis via Malonyl-CoA.-The starting point of this workmay be regarded as the introduction of the pigeon liver as a tissue for thestudy of fatty-acid synthesis.The enzymes involved in fatty-acid synthesisin this tissue have proved more amenable to isolation and purificationthan those of several other tissues studied. The system first prepared byBrady and Gurin consisted of a particle-free supernatant fraction supple-mented with a water-soluble extract of acetone-dried mitochondria. Pigeonlivers were homogenized at 0" in a phosphate-hydrogen carbonate bufferand the homogenate was subjected to differential centrifugation. Thesoluble enzymes concerned in fatty-acid synthesis remained in the super-natant fiuid after centrifugation at 100,OOOg.An acetone-dried powder ofmitochondria, spun down from the homogenate a t 1 3 , 0 0 O g , was prepared.The enzyme system was obtained by triturating the acetone-dried powderwith the supernatant fluid and then centrifuging the resulting suspensiona t 25,OOOg. It was capable of converting acetate into long-chain fattyacids under aerobic conditions in the presence of Mg2+, DPN+, A'J'P, andCoASH. Anzerobica.lly, the rate of synthesis was only slightly reduced.Since fatty-acid oxidation is negligible under anzerobic conditions, thisfinding prompted Brady and G U I ~ to suggest that in this enzyme systemthe pathways of fatty-acid oxidation and synthesis might be Werent.The pigeon-liver system was later submitted to extensive purificationby Wakil and his co-workers at Wisconsin.Livers were blended withphosphate-hydrogen carbonate buffer (pH 9.0) and the resulting homogenatewas centrifuged at 100,OOOg. The clear supernatant liquid produced waMERCER: BIOSYNTHESIS O F FATTY ACIDS 357found to contain all the enzymes necessary for fatty-acid synthesis.30 Itwas then fractionated by differential saturation with ammonium sulphate.Pour fractions, designated R, (0-25”/, saturation), R, (25--40y0 satura-tion), R, (40-50% saturation), and R, (50-65% saturation), were obtained.Singly these fractions were inactive, but a mixture of R,, R,, and R,,together with the necessary co-factors, was capable of fatty-acid synthesis.Fraction R, was purified five-fold by treatment with calcium phosphategel, and fractions R, and R, were subjected to fractional precipitation withethanol.The active enzyme in R, was precipitated at 20-30y0 ethanolconcentration and was designated R23. Fraction R, produced R,, and R46,which were precipitated a t ethanol concentrations of 20-3070 and 50--60%,respectively. A reconstituted system of R, (gel treated), R23, R43, and R,,corresponded to a fifty-fold purification of the initial liver extract. Theco-factors required at this stage of purification were ATP, CoASH, DPNH,TPN, isocitrate, M n 2 + , lipoate, and glutathione.,, The system showed asharp optimum a t pH 6.5. Free palmitic acid, along with progressivelysmaller quantities of free myristic, lauric, and decanoic acid, were themain products. Short-chain fatty acids did not accumulate.32 Since thepigeon-liver system did not lend itself to large-scale preparations which weredesirable if the individual enzymes were to be isolated and purified, Tiefz 33examined chicken liver as possibly a more suitable starting material.Shewas able to fractionate a soluble extract into four fractions R,, R,, R,,and R,, identical, in enzymic properties and co-factor requirements, withthose of pigeon liver.Fractions R, and R, were further purified 34 by adsorption from potas-sium phosphate b a e r (0.005~1, pH 7-0) on to calcium phosphate gel. Thegel was then centrifuged and the supernatant liquid discarded. Theadsorbed enzymes were eluted from the gel with potassium phosphatebuffer ( 0 . 1 ~ ~ pH 7-0), then reprecipitated with ammonium sulphate.Theprecipitate was spun down and finally resuspended in potassium phosphatebuffer (O-OO~M, pH 7.0). The resulting enzyme solutions, designated R,,and R2g, were yellow or yellow-brown. It was found that, if acetyl-CoAwas substituted for acetate plus CoASH, the synthesis of long-chain fattyacids was catalysed by R,, and RSg without assistance from R,. . FractionR,, therefore, presumably contained acetothiokinase,22 which catalyses theformation of acetyl-CoA from acetate, CoASH, and ATP. Fractions Rlgand Rzg required, for the anaerobic conversion of acetyl-CoA into long-chainfatty acids, the presence of ATP, Mn2+, HCO,-, and TPNH. DPNH wasable to replace TPNH, although the rate of fatty-acid synthesis was less.Hydrogen carbonate (H14C0,-) was not incorporated into fatty acids duringactive synthesis from unlabelled acetyl-CoA. The course of fatty-acidsynthesis, when these two fractions were used, was followed by measuring30 S.J. Wakil, J. W. Porter, and D. M. Gibson, Biochim. Biophys. Acta, 1957,24,453.31 J. W. Porter, S. J. Wakil, A. Tietz, M. I. Jacob, and D. M. Gibson, Biochim.32 J. W. Porter and A. Tietz, Biochim. Biophys. Acta, 1957, 25, 41.33 A. Tietz, Biochim. Biophys. Acta, 1957, 25, 303.34D. M. Gibson, E. B. Titchener, and S. J. Wakil, Biochim. Biophys. Ada, 1958,Biophys. Acta, 1957, 25, 35.30, 376358 BIOLOGICAL CHEMISTRYthe rate of oxidation of TPNH spectroscopicdy (decrease in optical densityat 340 mp) 35 and by measurement of the radioactivity of the long-chainfatty acids produced from [ 1-1W]acetyl-CoA.30 By using the spectro-photometric assay technique, Wakil, Titchener, and Gibson 36 found thatthe stoicheiometry of fatty-acid synthesis could be expressed by equation (5).Rig+ R2g 8Acetyl-CoA + 16ATP + 16TPNH + 16H+ HCOI-,M~'+~ Palmitic acid+ 16ADP + l6Pi + 16TPN + 8CoASH ( 5 )However, they noted that theoretically only 14 moles of TPNH should beconsumed per 8 moles of acetyl-CoA, since the last carbonyl group of acetyl-CoA, which constitutes the carboxyl group of palmitic acid, is not reduced.They also admitted that the exact proportion of ATP utilized was notclear.The r6le of ATP was also unknown; it was not used for the regenera-tion of acetyl-CoA since acetothiokinase was absent from R,, and R2g.It was postulated that it could function in the actiiration of hydrogencarbonate.R,, and RZg contained little or none of the enzymes of /?-oxida-tion. Acyl dehydrogenases (the green and yellow enz~mes),3~9 38 thio-lase, lo, l1 acetothiokinase, 22 and octanoic thiokinase 39 were completelyabsent. Enoyl hydrase 1% l6 and ,8-hydroxyacyl dehydrogenase 1 1 9 14 werefound in very low concentrations. The TPNH-dependent ap-unsaturatedacyl-CoA reductase,lzy 13, l9 the key enzyme for elongation of short-chainfatty acids by reversal of the &oxidation cycle, was also absent from R,,and R2g.Fraction R,, was found to contain a large amount of protein-boundbiotin.35 The overall recovery of biotin in this fraction was about 20%of the original extract.The final concentration of biotin in Rlg was 200-250 mpg. per mg. of protein, which amounts to approximately 1 mole ofbiotin per 106 g . of protein. This value far exceeded any concentration ofprotein-bound biotin previously reported. The importance of biotin to theenzyme function of Rlg was shown by the inhibition, by low concentrationsof avidin, of the conversion of acetyl-CoA into palmitate. This inhibitioncould be relieved by preincubation of avidin with (+)-biotin. Wakil andGibson 40 have produced evidence that a biotin-containing enzyme partici-pates directly in fatty-acid biosynthesis.At the level of purity to which fractions Rlg and R,, had been brought,no intermediates in the synthetic pathway from acetyl-CoA could be demon-strated.Wakil 41 therefore purified these fractions further by ion-exchangechromatography on cellulose. With the resulting fractions, Rlgc and ROgc,it became possible to demonstrate a stepwise synthesis. When Rlgc was36 S. J. Wakil, E. B. Titchener, and D. M. Gibson, Biochim. Biophys. Acta, 1958,36 S . J. Wakil, E. B. Titchener, and D. M. Gibson, Biochim. Biophys. Acta, 1959,37 D. E. Green, S. Mii, H. R. Mahler, and R. M. Bock, J . BioE. Chem., 1954, 206, 1.38 F. L. Crane, S. Mii, J. G. Hauge, D. E. Green, and H. Beinert, J . BioZ. Chem.,29, 225.34, 227.-1956, 218, 701.39 H. R. Mahler, S. J. Wakil, and R. M. Bock, J . BioE. Chem., 1953, 204, 453.40 S. J. Wakil and D. M. Gibson, Biochh. Biophqs. Acta, 1960, 41, 122.41S, J.Wakil, J . Amer. Chem. Soc., 1958, 80, 6465MERCER: BIOSYNTHESIS O F FATTY ACIDS 359incubated with acetyl-CoA in the presence of Mn2+, ATP, and HC03-,and the mixture was boiled, an intermediate was fornped which, in thepresence of RBgc, was quantitatively converted into long-chain fatty acids.I n the absence of any of the four components (acetyl-CoA, Mn2+, ATP,and HC0,-) or of Rlgc, no intermediate was formed, as measured by TPNHoxidation in the second reaction catalysed by Rzgc. Wakil 41 found thatthe intermediate had the following properties: (1) it moved with a differentRF(0.5) from acetyl-CoA in an ethanol-acetate chromatographic system ;(2) it arose from acetyl-CoA and carbon dioxide in equal amounts, as shownby radioactivity measurements ; (3) it could be converted quantitativelyinto long-chain fatty acids by Rtgc in the presence of TPNH ; (4) on hydrolysisand subsequent extraction, an acid was isolated which contained all theoriginal radioactivity, whether derived from [ 14C]acetyl-CoA or H14C03-;this acid was chromatographically indistinguishable from malonic acid ;malonic acid was isolated in the presence of carrier and recrystallized toconstant specific activity.Wakil concluded that the first step in fatty-acid synthesis is the carboxylation of acetyl-CoA to a malonyl derivativecatalysed by the biotin-containing Rlgc fraction in the presence of Mn2+and ATP, and that this was followed by successive condensation and reduc-tion catalysed by R2gc in the presence of TPNH.Malonic acid, as such,was not the intermediate.Malonic acid had previously been implicated in fatty-acid biosynthesisby PopjAk and T i e t ~ , ~ ~ who reported that it stimulated the incorporationof acetate into fatty acids by a soluble enzyme system isolated from themammary glands of lactating rats. The first clue as to the identity of themalonic acid derivative was provided by Brady 43 who was also using enzymepreparations from pigeon liver, although in not such a purified state as Rlgcand Rzgc. was purified byusing the modifications of Wakil et u Z . , ~ O and fractions precipitated betweeno-30~0 (Fraction I) and 30-40~0 (Fraction 11) saturation with ammoniumsulphate were obtained. When either of these fractions was incubatedwith acetaldehyde, malonyl-CoA, and Mn2 f, fatty acyl-CoA derivativeswere formed.Acetyl-CoA could not replace malonyl-CoA. On the basisof these results, Brady postulated that a molecule of acetyl-CoA or fattyacyl-CoA was reduced enzymically, in the presence of TPNH, to acet-aldehyde or the corresponding fatty aldehyde, which then condensed withthe activated methylene carbon atom of malonyl-CoA, the carboxyl groupof which is displaced as carbon dioxide [eqns. (6) and (7)]. The product of( 6 )RCHO + H02C*CH2C0.SCoA + R*CH(OH)*CH,.CO-SCoA + C02 (7 )these reactions would be /3-hydroxy-fatty acyl-CoA, which could be dehy-drated and then reduced with it second molecule of TPNH to produce afatty acyl-CoA derivative, and this could be cycled through these reactionsagain.Malonyl-CoA was postulated as arising from acetyl-CoA, ATP andcarbon dioxide in a reaction resembling the carboxylation of propionyl-CoAThe preparation used by Brady and GurinR*CO.SCoA + TPNH + H++ RCHO + CoASH + TPN+42 G. Popjsik and A. Tietz, Biochern. J., 1955, 60, 147.r3R. 0. Brdy, Proc. Nat. Acad. Sci. U.S.A., 1958, 44, 993360 BIOLOGICAL CHEMISTRYto methylmalonyl-CoA. In this work Brady cited, as evidence for thereduction of acetyl-CoA to acetaldehyde by TPNH, the oxidation of TPNHmeasured spectrophotometrically when Fraction I, acetyl-CoA, and TPNHwere incubated together. However, he put forward no chemical evidencefor the production of acetaldehyde. The disappearance of TPNH couldequally be interpreted as a reductive step in Wakil's scheme 41 [eqn.(S)].Acetyl-CoA + Malonic acid derivative - Butyryl-CoA + CO, ( 8 )Indeed, since Brady did not compare fatty-acid production by his enzymepreparation from acetyl-CoA and from malonyl-CoA, it is difficult to assessthe importance of acetaldehyde as a precursor of fatty acids. It couldwell be that very little acetaldehyde was incorporated into fatty acids.Wakil and Ganguly 44 found that the malonyl-CoA, in the absence ofacetyl-CoA, formed palmitate in the presence of TPNH and RSgc. Thiswas due to an enzyme present in RSgc which was capable of decarboxylatingmalonyl-CoA to acetyl-CoA. The acetyl-CoA so produced could then con-dense with residual malonyl-CoA in the usual way. It is not unlikely thatthis enzyme was present in Brady's fraction.However, the work of Bradyindicated that malonyl-CoA was the malonic acid derivative involved infatty-acid biosynthesis. Formica and Brady 45 went on to study theenzymic carboxylation of acetyl-CoA. They used extracts of pig heartprepared by the method of Bachhawat and Coon 46 and dialysed against Trisbuffer pH 7.4, and also Fraction I from pigeon liver. Enzymes present inthese systems catalysed the fixation of Hl4CO3-. The reaction catalysedby the pig-heart system was dependent upon the presence of ATP, acetyl-CoA, and Mg2+, whilst fixation by the pigeon-liver fraction required ATPand magnesium chloride and was enhanced by acetyl-CoA. The productof these reactions was identified as malonyl-CoA by isolation as the hydrox-amic acid derivative and comparison of its chromatographic behaviour withthat of authentic monomalonyl hydroxamic acid.Thus, the first step in fatty-acid synthesis in these systems appears tobe the carboxylation of acetyl-CoA to form malonyl-CoA by a biotin-containing enzyme system in the presence of ATP and a bivalent-metalion [eqn.(9)].Rlgc Acetyl-CoA + C 0 2 + ATP -----+ Malonyl-CoA + ADP + Pi (9)Malonyl-CoA was readily converted into palmitate by fraction Rggcand TPNH.41 Addition of acetyl-CoA significantly increased the rate andextent of palmitate synthesis by this fraction.44 Further, a significantamount of [ 14C]acetyl-CoA was incorporated into palmitate when unlabelledmalonyl-CoA was used. The amount of label introduced corresponded toan eighth of the total C, units converted into palmitate (measured byTPNH oxidation).Unlabelled acetaldehyde did not reduce the amount of[ Wlacetyl-CoA incorporated into palmitate, nor was acetaldehyde formed+ TPNHbiotin, Mn*+4 4 s . J. Warn and J. Ganguly, J . Amer. Chern. SOC., 1959, 81, 2597.45 J. V. Formica and R. 0. Brady, J . Amer. Chem. Soc., 1959, 81, 752.4'3B. K. Bachhewat and M. J. Coon, J . BioE. Chem., 1958, 231, 625MERCER: BIOSYNTHESIS OF FATTY ACIDS 361by enzymic reduction of acetyl-CoA by TPNH. Wakil and Ganguly 44also found that [ 14C]butyryl-CoA and [ 14C]octanoyl-CoA, as well as acetyl-CoA, could be incorporated into palmitate by Rsgc in the presence of malonyl-CoA. They also showed that enoyl hydrase,15, l6 p-hydroxyacyl dehydro-genase,ll, l4 and thiolase lo, l1 were absent from RZgc; Rzg did containvery low concentrations of the first two enzymes.34 Rage could not catalyseoxidation of TPNH by acetyl-CoA, acetoacetyl-CoA, /3-hydroxybutyryl-CoA, crotonyl-CoA, butyryl-CoA, hex-2-enoyl-CoA, or octanoyl-CoA.Thusoxidation of TPNH in this fraction required the presence of malonyl-CoAand some unsubstituted fatty acyl CoA (C2, C,, c6, etc.). None of thesubstituted intermediates of the ,&oxidation cycle was able to replace thesefatty acyl-CoA esters. On the basis of these observations, Wakil andGanguly 44 proposed reactions (10) and (11) as the biosynthetic pathway forBiotin containingRlgc + Mnz+CH,-CO.SCoA + CO, + ATP-H02C*CH2*CO*SCoA + ADP + Pi (10)[ 3 denotes hypotheticalintermediateR2gc CH,.CO*SCoA + HO,C*CH,*CO*SCoA + [CH,*CO*CH(CO,H)*CO-SCoA] (1 1 )Acetomalonyl CoA 4 TPNH[CH,*CH( OH) *CH(CO,H)*CO.SCoA] 4 --H,O[CH,*CH=C (CO,H)*CO*SCoA] 4 TPNH[CH,.CH,.CH(CO,H) CO-SCoA] 3.-COBCH,-CH,*CH,*CO*SCoAButyql-CoAfatty acids. The butyryl-CoA so formed could then condense with anothermolecule of malonyl-CoA with the formation of another p-oxo-dicarboxylicacid (butyromalonyl-CoA) which, after reductive decarboxylation, wouldgive rise to hexanoyl-CoA. This cycle would then be repeated until palm-itoyl-CoA was formed, whereupon deacylation would take place.According to this hypothetical pathway butyryl-CoA should be incor-porated intact into palmitate. This takes place,4,3 48 but since the abilityof butyryl-CoA and longer homologues of acyl-CoA derivatives to act assubstitutes for acetyl-CoA is very small and decreases sharply with increasingchain length, 49 and since trapping techniques designed to isolate thesecompounds have not been successfu1,49 the accuracy of the hypothesisbecame doubtful.Moreover, a report 5O of the isolation of C, and C,dicarboxylic acids, after condensation of acetyl-CoA and butyryl-CoA,4 7 R. W. Long, Fed. Proc., 1958, 17, 265.48R. W. Long and J. W. Porter, J. Biol. Chem., 1959, 234, 1406.49R. Bressler and S. J. Wakil, J . Bwl Chem., 1961, 236, 1643.so A. E. Steberl, G. W. Wasson, and J. W. Porter, Riochem. Biophys. Res. Comm.,1960, 2, 174362 BIOLOGICAL CHEMISTRYrespectively, with malonyl-CoA, could not be verified by either Brady 51or WakiLSoThe work of Brady et ~ 1 .~ ~ 9 52 threw more light on the mechanism ofacetyl-CoA-malonyl-CoA condensation. Brady, Bradley, and Trams, 52 usinga supernatant fraction obtained after high-speed centrifugation of cell-free suspensions of rat liver, showed that short-chain fatty acyl-CoA deriva-tives, in the presence of malonyl-CoA and TPNH, were incorporated intolong-chain fatty acids. When acetyl-CoA was incubated with malonyl-CoAand TPNH, the palmitic acid produced was derived from 1 mol. of acetyl-CoA and 7 mol. of malonyl-CoA. This enzyme preparation had markedmalonyl-CoA decarboxylase activity, which was non-competitively inhibitedby short-chain acyl-CoA derivatives.The presence of this enzyme renderedthe elucidation of the reaction sequence of fatty-acid synthesis difficult.However, Brady found that an enzyme preparation from young-rat brain,which was very active in fatty-acid synthesis, could be obtained free frommalonyl-CoA decarboxylase. 51 By using this preparation, Brady showedthat displacement of the non-esterified carboxyl-carbon atom from [ 1,3-14C2]-malonyl-CoA occurred upon addition of acetyl-CoA or butyryl-CoA in theabsence of TPNH. Decarboxylation was proportional to the quantity ofenzyme used and did not increase with time. These observations suggestedthat decarboxylation of malonyl-CoA took place concomitantly with itscondensation with acyl-CoA and before any reducing reactions, and thatthe product of the condensation was bound to the enzyme.Studies witharsenite suggested that vicinal enzyme-thiol groups participated in thecondensation and in the subsequent reduction. Similar observations hadbeen reported by Lynen, Kessel, and Eggerer, 53 using enzyme preparationsfrom yeast, and they indicated that the second step [reaction (ll)] of thepathway envisaged by Wakil and Ganguly 44 was incorrect. Bressler andWakil,49 in a thorough reinvestigation of this reaction, have recently con-firmed that decarboxylation of malonyl-CoA occurs during the condensationand before the reductive steps. They used a pigeon-liver preparation whichrepresented a 3000-fold purification in comparison with the original extract.This preparation, designated R,,, was 'obtained from Regc by, first, dialysisagainst phosphate buffer (O-OO~M, pH 7.0) and then chromatography on acolumn of calcium apatite, with 0*05~-phosphate buffer (pH 7.0) as theeluant.The fractions of eluant containing the enzyme were pooled andthe enzyme precipitated with ammonium sulphate. The malonyl-CoAdecarboxylase content of R,, was very low, a fact which enabled the depen-dence of palmitic acid production, from malonyl-CoA and TPNH, on acetyl-CoA to be demonstrated. However, acetyl-CoA could be replaced bypropionyl-CoA and, to a small extent, by butyryl-CoA. When propionyl-CoA was used instead of acetyl-CoA, the product of the reaction was a C,,fatty acid. Thus, the occurrence of fatty acids with odd numbers of carbonatoms in animal tissues may well depend on the availability of propionyl-CoA61 R.0. Brady, J. Biol. Chem., 1960, 235, 3099.62 R. 0. Brady, R. M. Bradley, and E. G. Trams, J. Biol. Chem., 1960, 235, 3093.68 F. Lynen, I. Kessel, and H. Eggerer, A Report to the Bayer Akademi des Mathe-mrttisch und Naturwissenschaft Klasse, 1960MERCER: BIOSYNTHESIS O F FATTY ACIDS 363rather than on the presence of another enzyme system. When butyryl-CoA was substituted for acetyl-CoA, the primary product of synthesis wasshown to be a C,, acid (stearic). These results indicated that in all threeinstances, with acetyl-CoA, propionyl-CoA, or butyryl-CoA as startingmaterial, 7 mol. of malonyl-CoA were added to each of these acyl-CoAderivatives with the formation of C16, C,,, and C,, acids, respectively.Byusing [ 1 -14CIacyl-CoA derivatives it was shown that acetyl-CoA contributesto C-15 and (3-16 of palmitic acid, propionyl-CoA to (3-15, C-16, and C-17of the C,, acid, and butyryl-CoA to C-15, C-16, (2-17, and C-18 of stearicacid. The stoicheiometric relations between acetyl-CoA, malonyl-CoA, andTPNH could be expressed by equation (12). Thus one C, unit of palmitateCH,-CO-SCoA + 7H02C*CH,*CO*SCoA + 14TPNH + 14H+ +(12)is derived from acetyl-CoA and the remaining 14 carbon atoms are derivedfrom 7 mol. of malonyl-CoA. The same stoicheiometry holds if propionyl-CoA or butyryl-CoA is substituted for acetyl-CoA.The incorporation of tritiated acetyl-CoA (CT,*CO*SCoA) and malonyl-CoA (HO,C*CT,*CO*SCoA) into fatty acids by R,, was then studied.WhenCT,*CO*SCoA was incubated with unlabelled malonyl-CoA, TPNH, andR2a, it was found that 6 atoms of tritium were incorporated into 1 moleof palmitic acid. This corresponded with the stoicheiometry expressed inequation (12) and indicated that the methyl groups of acetyl-CoA areincorporated as a unit into palmitic acid. When HO,C*CT,*CO*SCoA wasincubated with unlabelled acetyl-CoA, TPNH, and R2a, the incorporationof tritium into palmitic acid was 5-6-8 atoms per mole of palmitic acid.This finding was again in agreement with the stoicheiometry, but it alsoindicated that decarboxylation of malonyl-CoA must have taken place con-comitantly with its condensation with acetyl-CoA, confirming the findingsof Brady 51 and Lynen et aE.53 in disproving the scheme of Wakil andG a n g ~ l y .~ ~ If a dicarboxylic acid had been an intermediate in fatty-acidsynthesis, no tritium would have been incorporated into palmitate fromHO,C*CT,*CO*SCoA.Incubation of acetyl-CoA and H0,14C*CH,*CO*SCoA with R,, in theabsence of TPNH, caused the liberation of l*CO, and the accumulation ofa condensation product which has not yet been identified. This conden-sation product was isolated by paper chromatography. On hydrolysis ityielded an acid which was extractable with ether and was chromatographic-ally separable from acetoacetic, crotonic, malonic, 8-hydroxybutyric, butyric,octanoic, and palmitic acid. The compound did not accumulate if TPNHwas added to the reaction mixture, palmitic acid being the primary product.This suggested that the condensation product is a true intermediate in theconversion of acetyl-CoA and malonyl-CoA into palmitate and that itsreduction is faster than its formation.Bressler and Wakil 49 suggest that, since carbon dioxide is released con-comitantly with the condensation of acetyl-CoA and malonyl-CoA, themechanism may involve the formation, on the enzyme surface, of a negativelycharged intermediate such as -CH,*CO*SCoA from malonyl-CoA, whichCH,*[CH2],4*C02H + 14TPN+ + 7C0, + 8CoASH + 6H2364 BIOLOGICAL CHEMISTRYcould .then condense with the partly positively charged carbonyl group ofacetyl-CoA FH,*C+(O-)*SCoA] to form a keto-derivative [eqns.(13) and (14)].-O*CO*CH,-CO*SCoA + Enzyme + COz + [ -CH,*CO*SCoA]Enzpe (1 3 )CH,C-SCoA + [-CH,*CO-SCoA]Enzyme-+ [CH,*CO*CH,*CO*SCoA]Enzyme (14)4-I 0-The nature of the keto-compound is not yet known.Lynen at aZ.53 postu-lated that an acetoacetyl derivative of the enzyme (CH,*CO*CH2CO*S*Enz)is formed by condensation of acetyl-CoA and malonyl-S-Enzyme. How-ever, the compound accumulating in the Bressler and Wakil system did notappear to be an acetoacetyl derivative (from its chromatographic behaviour).Bressler and Wakil favour a modification of an earlier hypothesis proposedby L ~ n e n , ~ * involving the formation of a polyketo-polymer of C, units.They suggest that a polyketo-compound is formed in conjunction witheither the enzyme, CoASH, or an, as yet, unknown factor, and that it isreleased only after it attains a specific length of 16 carbon atoms.TPNHwould then reduce this compound to palmitoyl-CoA, conceivably by reduc-tion of the enol form and simultaneous removal of water.Ganguly 55 showed that the malonyl-CoA system is present in manyanimal tissues, namely, liver, brain, pancreas, lungs, kidneys, small intestine,mammary gland, adipose tissue, and suprarenal fat of the ox, and liver andovary of the chicken. Brady and his co-workers 519 52 demonstrated itspresence in rat liver and brain. However, the enzyme system of rat brainshowed significant differences, in that acetyl-CoA, /?-hydroxybutyric acid,and crotonic acid all caused the oxidation of TPNH and were incorporatedinto long-chain fatty acids. These compounds do not oxidize TPNH inthe presence of the purified avian-liver enzymes, nor are they incorporatedinto palmitate.Vagelos and his co-workers 56 obtained a soluble enzymesystem from rat epididymal adipose tissue which requires 1 mole of acetyl-CoA, 6-5 moles of malonyl-CoA, and 14.7 moles of TPNH for the synthesisof 1 mole of palmitic acid. This system will also catalyse the synthesis ofodd-numbered, iso-, and anteiso-long-chain acids from odd-numbered, iso-,and anteiso-short-chain fatty acyl-CoA derivatives plus malonyl-CoA andTPNH. 57 Early experiments with cell-free preparations of lactating-ratmammary gland showed that, under zxobic conditions, acetate was incos-porated into long-chain fatty acids in the presence of ATP and pyruvate,oxaloacetate, or cc-oxoglutarate.58 A soluble enzyme system (MGE),produced after centrifugation of the mammary homogenate at l04,000g,had an absolute requirement for ATP and was stimulated by oxaloacetate,succinate, and a-oxoglutarate ; malonate, however, also produced a verymarked stimulation.42 DPN and CqASH were essential to the activity54 F. Lynen, J. Cell. Comp. Physiol., 1959, 54, sup. 1, 33,55 J. Ganguly, Biochim. Biophys. Actu, 1960, 40, 110.56D. B. Martin, M. G. Homing, and R. Vagelos, J. Biol. Chem., 1961, 236, 663.57 M. G. Horning, D. B. Martin, A. Karmen, and R. Vagelos, J. Biol. Chew., 1961,58 G. PopjBk and A. Tietz, Biochem. J . , 1954, 56, 46.236, 669MERCER: BIOSYNTHESIS O F FATTY ACIDS 365of MGE.S9 Dils and Popjak60 have recently shown that a particle-freesupernatant fraction from rat mammary gland incorporated acetate intosaturated fatty acids (c6-418) in the presence of ATP, CoASH, TPNH,HCO,-, and &2+.Malonate strongly stimulated synthesis, but [2-l4C]-malonic acid was not incorporated into the fatty acids produced, presumablybecause of the absence of malonic kinase in the enzyme system. Theaddition of avidin, in the presence of optimal amounts of malonate andHCO, -, resulted in almost complete inhibition of fatty-acid synthesis fromacetate. Abraham et aE.61 showed that avidin also suppressed fatty-acidsynthesis from acetate in the mammary gland in the absence of addedmalonate.Zebeand McShan62 showed that the fat body of the moth Prodenia eriduniaincorporates acetate into palmitic acid in the presence of malonate, ATP,CoASH, and glutathione or cysteine. Tietz 63 detected its presence in cell-free preparations of the fat body of the locust, Locusta migratoria.Higher plants possess the malonyl-CoA system; Stumpf and Barber 64found that avocado fruit mesocarp mitochondria could incorporate [ 14C]-acetate into esterified long-chain fatty acids in the presence of ATP, CoASH,and Mn2+.Mudd and Stumpf,65 in a re-examination of this system, con-firmed that the primary site of fatty-acid synthesis is in the mitochondria.The fatty acids produced were mainly associated with triglycerides andphospholipids. Elongation of existing fatty acids by the addition of acetatecould not be demonstrated. Aqueous extracts of acetone-dried avocadomitochondria incorporate acetate into oleic and palmitic acids in the presenceof ATP, CoASH, manganous chloride, potassium hydrogen carbonate, oliveoil, TPN, and cysteine.66 Hydrogen carbonate, although essential, was notincorporated into either long-chain or volatile fatty acids.Acetyl-CoAfunctions as a substrate for this enzyme preparation with the same co-factorrequirements, including that for ATP.67 Avidin proved to be a potentinhibitor, although preincubation with stoicheiometric quantities of biotinreversed this inhibition. Biotin also stimulates the incorporation of[I4C]acetate into oleic acid and at least two other unsaturated fatty acids(chromatographically identified as linoleic and linolenic acids) in develop-ing flax embryos.68 Barron, Squires, and Stumpf,Gg using aqueous extractsof acetone-dried mitochondria, showed that the incorporation of [ l*C]acetyl-CoA into long-chain fatty acids required ATP and carbon dioxide and wassensitive to avidin, whereas the incorporation of 14C in malonyl-CoA requiredThe malonyl-CoA system also appears to be present in insects.5gA.Tietz and G. Popjak, Biochem. J., 1955, 60, 155.soR. Dils and G. Popjak, Biochem. J., 1961, 80, 4 7 ~ .S. Abraham, K. J. Mathes, and I. L. Chaikoff, Bioci~im. Biophys. Acta., 1961,s2E. C . Zebe and W. H. McShan, Biochim. Biophys. Acta, 1959, 31, 513.63A. Tietz, Preprint No. 60, Symposium No. VII, Vth International Congress of65B. Mudd and P. K. Stumpf, J . Biol. Chem., 1961, 236, 2602.6 6 C.L. Squires, P. K. Stumpf, and C. Schmid, Plant Physiol., 1958, 33, 365.6 7 C. L. Squires and P. K. Stumpf, Fed. Proc., 1959, 18, 329.saE. B. Kurtz and A. Miramon, Arch. Biochem. Biophys., 1958, 7'7, 514.6a E. J. Barron, C. L. Squires, and P. K. Stumpf, J . Biol. Chem., 1961, 236, 261046, 197.Biochemistry, 1961.K. Stumpf and G. A. Barber, J . Biol. Chem., 1957, 227, 407366 BIOLOGICAL CHEMISTRYneither ATP nor carbon dioxide and was insensitive to avidin. The fattyacids so produced represented a synthesis de nouo and not an elongation ofexisting fatty acids. Of the fatty acids synthesized, 2% were found in thenon-saponifiable fraction, 5% as free fatty acids, 4% as monoglyceride,11% as diglyceride, 33% as triglyceride, and 44% as phospholipid.found that the enzymes responsible for esterification ofthe fatty acids synthesized could be removed from mitochondria1 extractsby centrifugation at 140,OOOg for 90 min., a small pellet being obtainedwhich had no capacity to form fatty acids from acetate but rapidlyincorporated palmitate or stearate into triglycerides in the presence of ATPand CoASH.The supernatant fluid retained the capacity to synthesizepalmitate and stearate from acetate, but these acids remained unesterified.The mechanism of fatty-acid synthesis in higher plants, therefore, appearsto be identical with the malonyl-CoA system of animal tissues. However,there is a fundamental difference in the site of the enzymes concerned;in animal tissues they are located in the cytoplasm whereas in higher plantsthey are found in the mitochondria.It is also of interest that the fatty-acid-elongating system, which is present in animal mitochondria, appearsto be absent from the avocado mitochondria.Yeast homogenates were also shown by Klein 70 to incorporate acetateinto fat in the presence of carbon dioxide. Lynen et ~ 1 . ~ ~ have demonstratedthe presence of the malonyl-CoA system in cell-free yeast extracts.The organism Clostridium kluyveri appears to possess a variation of themalonyl-CoA pathway. Vagelos et ~ 1 . 7 ~ 1 72 showed that enzyme preparationsof this organism catalyse an exchange reaction between malonyl-CoA andHl*CO,- which is completely dependent on the addition of boiled cellextract and partly dependent upon acetyl-CoA and a thiol.The activefactor of the boiled cell extract was identified as hexanoic acid. Hexanoyl-CoA could replace the requirements for both boiled cell extract and acetyl-CoA. Malonyl-CoA was not decarboxylated by the enzyme preparation, norwas acetyl-CoA incorporated into malonyl-CoA. The enzyme, purified some75-fold, appears to catalyse a reversible condensation of malonyl-CoA andBarron etHO*O14C*CH,*CO-SCoA + CH,*[CH,],*CO*SCoA + 14C02 + CoASH +(CH3*[CH,I,C0*CH,*Co*SCoA} (15 ){ 1 = possible producthexanoyl-CoA, coupled with a decarboxylation, such as is shown in scheme(15). However, the product of this reaction has not yet been identified.It is suggested that this reaction could be involved in fatty-acid biosyn-thesis, since it could provide a source of malonyl-CoA other than thebiotin-dependent carboxylation of acetyl-CoA.E.I. M.70 33. P. Klein, J. Bact., 1957, 73, 530.TIP. L. Vagelos, J . Amer. Chem. SOC., 1959, 81, 4119.7aP. R. Vagelos and A. W. Alberts, J . Biol. Ch., 1960, 235, 2786TRISTRAM AND STEVEN: COLLAGEN 3672. COLLAGENCOLLAGEN is present in many physically distinct forms of tissue within theanimal body, for example, skin, cartilage, tendon, bone, myofibril, andcornea, each form of collagen complex performing a specialised structuralfunction. Tissue collagen is almost insoluble and is relatively inert meta-bolically; it is often associated with the so-called ground substance ormucopolysaccharide.1 Nageotte 2 first isolated an acid-soluble collagenwhich later led to the modern work on soluble collagens and their chemical,physical, and biological relations to the insoluble collagen of connectivetissue.A number of soluble collagens have now been isolated from differentcollagenous tissues by mild extraction, employing neutral salt, buffer, orweakly alkaline or weakly acidic solutions. The interrelations of thesesoluble collagens and insoluble collagen will be briefly discussed in thisReport. Molecular weights of some soluble collagens are given in Table 1.TABLE 1. Physical molecular weights of soluble collagensMolecular weightSource Extract Name ( x 10-5) Ref.Carp swim bladder Acid Ichthyocol 3.0-3.5 3Calf skin Neutral salt Tropocollagen 3.4 4Calf skin Acid Procollagen 7-0 5Rat tail Neutral salt 5.0 6Rabbit skin Neutral salt 5.0 7Orekhovitch and Shpikiter 5 later concluded that tropocollagen and pro-collagen were identical, although this did not explain the differences inreported molecular weights and amino-acid analyses (see Table 3).Boedtker and Doty 3 determined the physical dimensions of ichthyocol insolution and deduced that the collagen had a rod-shaped molecule of dimen-sions 2900 x 14 8.Hall and Doty were able to determine the dimensionsof the smallest particle of an ichthyocol preparation examined by electron-microscopy; the value obtained, 2450 x 15 8, was in such good agreementwith the calculated value for ichthyocol in solution that they concluded thatthe particles observed in the electron microscope were individual collagenmolecules.Similar preparations were redissolved and they exhibited allthe physical characteristics of ichthyocol, thus proving that no physicaldegradation had taken place during the preparation of samples for electron-microscopy.Three physically distinct collagenous proteins were isolated from skin,9, 10D. S. Jackson in “ Nature and Structure of Collagen,” ed. J. T. Randall, Butter-worths Scientific Publns., London, 1953, p. 177.J. Nageotte, Compt. rend., 1927, 184, 115.3 H . Boedtker and P. Doty, J . Amer. Chem. SOC., 1955, 77, 248.J . Gross, Nature, 1958, 181, 556.sV. N. Orekhovitch and V. 0. Shpikiter, Science, 1958, 127, 1371,saV. N. Orekhovitch, V. 0. Shpikiter, V. I. Mazourov, and 0.V. Kounina,Bull. SOC. Chirn. biol., 1960, 42, 505.‘jN. H. Grant and H. E. Alburn, Arch. Biochem., 1960, 89, 262.J. H. Fessler, Biochem. J . , 1960, 76, 452.C. E. Hall and P. Doty, J . Amer. Chem. SOC., 1958, 80, 1269.R. D. Harkness, A. M. Marko, H. M. Muir, and A. Neuberger in “ Nature andStructure of Collagen, ” ed. J. T. Randall, Butterworths Scientific Publns., London,1953, p. 208.l o D. S. Jackson, A. A. Leach, and S. Jacobs, Biochim. Biophys. Acta, 1958,27,418368 BIOLOGICAL CHEMISTRYan alkali-soluble, an acid-soluble, and a residual insoluble collagen fraction.Two other soluble proteins were also found to be associated with collagenin skin g-One was rich in tyrosine and perhaps identical with a similar pro-tein described by Bowes et al.ll These non-collagenous proteins, as wellas the mucopolysaccharide, may be involved in the matrix of skin collagen.Fessler has demonstrated the presence of three sub-fractions of a neutral-salt-soluble collagen obtained from rabbit skin.Jackson l2 suggested thatin the process of fibrogenesis neutral-salt-soluble collagen was modified to anacid-soluble collagen which was in turn polymerised to insoluble collagen.Polymerisation can take place by cross-linkage between tropocollagenmolecules, arranged in parallel, by hydrogen- bonding and/or covalent link-age,4 as well as by end-to-end aggregation.13 The progressive increase inthe number of cross-linkages between collagen molecules is accompanied bya corresponding decrease in the ability of the collagen aggregate to dissolvein dilute acid solutions.14 Young tissue contains a much greater propor-tion of soluble collagen than does aged ti~sue.1~ The maturing of colla-qen 15 is thought to be associated with an increase in cross-linkages witha resultant stiffening of the collagen fibres.Bowes et aZ.ll suggested thatthe tyrosine-rich soluble protein of skin may be essential for the conver-sion of soluble collagens into the insoluble form.Soluble collagens under certain environmental conditions aggregate tore-form insoluble bundles of fibres. Gross described the formation of threephysically distinct types of collagen fibre from a tropocollagen solution inthe presence of ’certain physiological metabolites. The physical differencesin these fibres, as demonstrated by electron-microscopy, was considered tobe caused by different types of alignment of the tropocollagen monomersduring the process of fibre formation (see Table 2).49 16 The chemicaldifferences between soluble collagens have been deduced from the compositionof the thermal depolymbrisation products and this subject has been wellTABLE 2.Types of collagen Jibres prepared from tropocollagenPreparative technique Spacing Description Ref.2 Dialysis 640 NativeSodium chloride 640 Native 1612Glycoprotein 1500-3000 Fibrous long spacing 41500-3000 Segment long spacing 4 ATPAmmonium sulphate(A)I Nodular 16bl1 J. H. Bowes, R. G. Elliott, and J. A. Moss in “ Nature and Structure of Collagen,”ed. J. T. Randall, Butterworths Scientitic Publns., London, 1953, p.199.l2 D. S. Jackson in “ Recent Advances in Gelatine and Glue Research,” ed. G ,Stainsby, Pergamon, London, 1958, p. 50.l3 A. J. Hodge, J. H. Highberger, G. G. J. Deffner, and F. 0. Schmitt, Proc. Nut.Acad. Sci. U.S.A., 1960, 48, 197.14 K. H. Gustavson, “ The Chemical Reactivity of Collagen,’’ Academic Press,New York, 1956.l6 D. S. Jackson in “ Connective Tissue Symposium,” ed. R. E. Tunbridge et ul.,Blackwell Press, Oxford,“ 1957, p. 62.16 F. 0. Schmitt in Connective Tissue, Thrombosis, and Atheroschlerosis,” ed.I. H. Page, Academic Press, New York, 1959, p. 43.16 (a) F. 0. Schmitt, J. Gross, and J. H. Highberger in S. E. B. Symposia No. 9,“Fibrous Proteins and their Biological Significance,” 1955, p.148; ( b ) L. D. Kahn,R. J. Carroll, and L. P. Witnauer, Biochim. Biophys. Acta, 1961, 50, 592TRISTRAM AND STEVEN: COLLAGEN 369reviewed by Orekhovitch et aZ.17 “ Collagen” means “glue-forming ” or“ gelatin-forming.” In general, collagens are readily depolymerised by heatin neutral solution or by soaking them in chemical depolymerising agents suchas compounds which break hydrogen bonds (e.g., urea) or lyotropic inor-ganic salts (e.g., calcium chloride). In the first case the intrahelical hydrogenbonds of collagen are disrupted by thermal agitation at a critical range oftemperature (shrinkage temperature). In the second the chemical reagentscompete with the interchain peptide bonds for attachment by hydrogen-bonding or as co-ordinated addition products, and thus break down thenatural hydrogen bonds of the protein which are essential for the maintenanceof the triple helix.14 Gustavson emphasised the r61e of hydroxyprolinein interchain hydrogen-bonding. The products from both of these typesof depolymerisation are soluble gelatins, according to Ward’s definition.18Gelatin was defined as the protein derived from collagen, and gelatine asthe impure commercial preparation.The collagen-gelatin transition is areversible process which takes place in three steps l9 which have charac-teristic reaction rates. 2O The commercial preparation of gelatine involvespretreatment of the collagen with acid or alkali before thermal depolymeri-sation with consequent rupture of peptide bonds and fragmentation of theoriginal collagen molecule.Commercial gelatines are further degradationproducts of gelatin and usually have molecular weights of 70,000--90,000as determined from the content of N-terminal residues (cf. Courts 21). Thepresent position of the commercial gelatines has been recently reviewed.18demonstrated the liberation of both free and peptide-bound hydroxyproline during the thermal depolymerisation of native collagenobtained from the corium layer of steer hide. This may indicate theimportance of non-protein nitrogen in the polymerisation of collagen mole-cules. Depolymerisation of the triple-helix structure of collagen is accom-panied by the formation of two polypeptide components which have therandom-coil configuration; the components were described as a- and /3-components.5 9 23 The p-component has approximately twice the molecularweight of the a, and on further degradation by heat at alkaline pH the p-component is ruptured with the formation of two cc-components. Orekho-vitch and his co-workers l7 suggested that the 6-component was in facttwo cc-components condensed together through an ester bridge ; this theorywould imply that the triple helix of native collagen was composed of threea-components, two of these being held together as a p-component; the long@-component could then be inter-wound with the single a-component in thecollagen helix. Chemical analysis 24 of the isolated cc- and ,%componentsVerz&r 22,l7 V. N. Orekhovitch, V. 0. Shpikiter, V. I.Mazourov, and 0. V. Kounina, Bull.18A. G. Ward, J . Internat. SOC. Leather Chemists, 1960, 44, 505.l e A . Veis, J. Anesey, and J. Cohen, Arch. Biochem., 1961, 94, 20.21A. Courts, Biochem. J., 1954, 58, 74.22F. Verz&r, Gerontologia, 1960, 4, 104.e2aA. Mayer and F. Verzh, Gerontologia, 1959, 3, 184.s3 J. Gross in “ Connective Tissue Symposium,” ed. R. E. Tunbridge et al., Black-24K. A. Piez, E. Weiss, and M. S. Lewis, J . Biol. Chem., 1960, 235, 1987.SOC. Chim. biol., 1960, 42, 505.W. F. Harrington and P. H. von Hippel, Arch. Biochem., 1961, 92, 100.well Press, Oxford, 1957, p. 45370 BIOLOGICAL CHEMISTRYsuggests that there are slight differences in amino-acid composition (cf.Table 3).The interrelations of the thermal degradation products are diagrammatic-ally shown in the Scheme.More recently Grassmann et ~ 1 . ~ ~ have describedDepolymerisation (M.W. 125,000)RepoIymerisatjon (n3*w. 290,000) 2a+GelatinSoIubIe collagene.g.9orProcollagenAcid/Alkali pretreatment Acid/AlkaliHot extraction ___+ Commercial gelatine (M.W. 70,000-90,000)a third component, the y-component, and a similar component has also beendetected by Wood 26 during the analysis of the sedimentation pattern ofthermally degraded neutral-salt-soluble collagen from rat skin. These threecomponents may be related in the manner shown in the Figure.25 This2~3~Pictorial repwsentation of denaturation of soluble collagen.(Reproduced, with permission, from Grassmann, Hannig, and Engel, 2. physiol.Chem.,1961, 324, 284.)scheme assumes three degrees of cross-linking within the soluble collagentriple helix, and it is implied that further rupture of these links in y- and p-components will produce three and two a-components, respectively.Lyotropic salt solutions have an action on collagen which is similar to26 W. Grmsmann, I(. Hannig, and J. Engel, 2. physiol. Chem., 1961, 824, 284, 71.26 G. C. Wood, Bwchem. J., 1962, 82, ZPTRISTRAM AND STEVEN: COLLAGEN 371thermal depolymerisation. l4 Sodium perchlorate dissolves insoluble colla-gen completely at room temperature after a threshold of 2M has beenexceeded. Calcium chloride depolymerises soluble collagen with a correspond-ing change in optical rotation which is typical for the collagen-gelatin tran-sition.27 The threshold concentration of lyotropic agents which is essentialfor the depolymerisation may be explained by Gustavson’s suggestion 14 thatundissociated molecules of the lyotropic agent are present a t the thresholdconcentration.These molecules co-ordinate with the peptide bonds withinthe triple helix and in doing so compete for the sites of hydrogen bonds;in consequence the stability of the helix is lost. Chvapil and Zahradnik 28followed the chemical shrinkage of rat-tail tendon in sodium perchloratesolution by measuring the corresponding change in length under tensionand observed that the contractile process was accompanied by liberationof a mucoprotein followed by solution of collagenous protein. The shrunkenfibres contained an insoluble collagen described as metacollagen.Sonic irradiation of tropocollagen 2 9 3 30 caused the progressive rupture ofpeptide bonds at intervals along the length of the peptide chains in thecollagen triple helix, with the formation of fragments of collagenous proteinwhich were incapable of end-to-end polymerisation to form a fibre.Grassmann et al.31 determined the amino-acid composition of procollagen ;Piez et aZ.24 fractionated the a- and p-components of heat-denatured collagenon carboxymethylcellulose columns. The amino-acid compositions of thesecomponents differed slightly between themselves and the intact collagen ;although it is not known if small amounts of peptide material were liberatedin this preparation, earlier work employing more vigorous conditions indi-cated the liberation of non-protein 32 nitrogen.If a small quantity of pep-tide material was liberated it could well account for slight differences in thecomposition of the fragments.The amino-acid compositions of procollagen, tropocollagen, and a- and@-components of tropocollagen are given in Table 3. It can be seen thatthese values for the intact collagens agree well. Until recently collagen wasthought to be found only in connective tissue. Lowther’s isolation 33 ofsoluble collagens from subcellular fractions ,suggests that a wider view ofthe distribution of collagen is necessary. Eastoe 34 has examined theamino-acid distribution in the subcellular soluble collagens obtained fromguinea-pig granuloma tissue.Although Eastoe points out that these solublecollagens were obtained in very small quantities and the analyses are tobe taken as a first approximation, we feel that their inclusion in this Tableis interesting for reasons of comparison. Nuclear and mitochondria1 solublecollagens have noticeably more hydroxy-amino-acids than procollagen and27S. Venkataraman, Proc. Indian Acad. Sci., 1960, 52A, 80.28M. Chvapil and R. Zahradnik, Biochim. Biophgs. Actu, 1960, 40, 329.2sA. J. Hodge and h. 0. Schmitt, Proc. Nut. Acad. Sci. U.S.A., 1958, 44, 418.Connective Tissue, Thrombosis, and Atheroschlerosis,” ed.31 W. Grassmann, K. Hannig, and M. Schleyer, 2. physiol. Chem., 1960, 322, 71.32 H. Rosen, A. Kessler, and S. M. Levenson, Arch. Biochem., 1960, 90, 167.33D.A. Lowther, N. M. Green, and J. A. Chapman, J . B&~phys. Biochem. CytoE.,34 J. E. Eastoe, Biochem. J., 1961, 79, 648.F. 0. Schmitt inI. H. Page, Academic Press, New York, 1959, p. 43.1961, 10, 373372 BIOLOGICAL CHEMISTRYTABLE 3. Amino-acid composition of soluble collagens and isolatedcc- and B-components presented as residues per 1000 total residuesAuthor Grassmann Piez 24Tissue Calf skin Calf skinCollagen Procollagen TropocollagenaComponent Total Total a 6 w47.6 45.1 42.7 45-975.8 71.3 74.0 68.7327.3 325.4 323-3 328.4107.8 111-7 117.6 108.9 AlaSer 29.2 37.2 38.0 37-5Thr 18.8 17.8 16.9 18-13.9 3.0 3.4 2.022.6 22.4 17.5 27-5 ValMet 4.5 6.4 6.5 6-3Ileu 12.2 10.3 9.5 14.5Leu 26.6 24.6 20.7 28-5Phe 14.7 13.3 13.6 14.5Pro 131.8 134.6 141.2 127.7Hypro 82.3 86.0 87.7 83.0His 6-5 5.0 2.6 6.028.8 26.7 30.0 22.85.1 7.3 5.9 8.854.5 50.7 49.6 51-26;:GlYTyrLYSHYlPk gc s 2 s 2- - - -Eastoe 34Guinea-pig granulomaNeutral-salt -solubleNuclear Mitochondria1 Microsomal48.3 54.0 61.668.2 71.7 76.0324.0 300-0 263.0100.7 101.8 93-444- 1 48.7 51.820.2 24.8 31.53.2 4-8 11-320.5 24.1 29-18.3 6.9 6.011.8 13.4 22-425.5 29.0 41.612-4 14.8 18-5115.6 109.8 101.5104.4 100.0 79-66.2 9.925.8 28-3 36.18.8 7.651.6 55-8 59-0Trace Trace Tracet- \bbrecently Piez et aLS4 have reported at least two types of a-component and twotypes of 8-component in tropocollagen ; the data recorded here do not, therefore,apply to single components.b Sum of His and Hylys = 12.4.tropocollagen. In microsomal collagen the increase in hydroxy-amino-acidsis confined to serine and threonine.Soluble collagens contain trace amounts of carbohydrate and nucleicacids which must not be ignored in any complete chemical structure ofcollagen.These collagens contain approximately 0.5% of hexosamine and0.2% of reducing Banga and Balo 37 isolated a mucopoly-saccharide containing glucose, mannose, galactose, and glucosamine fromthe digestion of Achilles tendon with a pancreatic mucoproteinase. Thecarbohydrate of collagen was retained during the acid-processing of gelatineebut lost after alkali g re treatment.^^ Traces of bound aldehyde 39 andnucleic acids 40 have also been detected in collagen and its derived gelatines.N - and C-Terminal analyses carried out on insoluble collagen indicatedno terminal amino-acids reacting under the experimental conditions.41 -4435, 3635 R. Consden in " Nature and Structure of Collagen," ed. J. T. Randall, Butter-3'31. Oneson and J. Zacharias, Arch. Biochem., 1960, 89, 271.37 I. Banga and J. Balo, Biochem. J., 1960, 74, 388.38A. Courts, Biochem. J., 1959, 73, 596.3 O J. M. Landucci, J. Pouradier, and M. Durante in " Recent Advances in Gelatine40 A. M. Venet and J. Pouradier, Science et Industries Photographiques, 1959,30,406.41J. H . Bowes and J. A. Moss, Nature, 1951, 168, 514.42 J. H. Bowes and R. H. Kenten, Biochem. J., 1948, 43, 365.43 C. C. Solomons and J. T. Irving, Biochem.J., 1958, 68, 499.44 W. Grassmann and H. Hormann, 2. physiol. Chem., 1953, 292, 24.worths Scient,ific Publns., London, 1953, p. 196.and Glue Research," ed. G. Stainsby, Pergamon, London, 1958, p. 62TRISTRAM AND STEVEN: COLLAGEN 373Bowes and Kenten 42 detected traces of N-terminal aspartic acid and alanineafter pretreatment of procollagen with hyaluronidase ; pretreatment withurea also exposed traces of these two terminal groups. A recent study ofthe reaction of fluorodinitrobenzene with calf-skin procollagen has demon-strated the presence of thirteen amino-acids reacting as N-terminal resi-dues.45, 46 These N-terminal residues were derived from a non-proteinnitrogen fraction (ca. 2% of the total protein nitrogen) which was physicallyassociated with the soluble collagen.47The partial reactivity of the &-amino-groups of lysine in collagen towardsselective reagents strongly suggests that about one-third of these groupsmay be masked in some form of peptide chain cross-link. This masking isnot removed by depolymerisation to gelatin, which thus precludes the pos-sibility of steric masking, and indicates some kind of chemical substitutionof the lysine residues.A selection of the reactivity of &-amino-groups oflysine towards various reagents is given in Table 4.TABLE 4. Reactivity of E-amino-groups of lysine in collagen and gelatineMaterialHide collagenHide collagenHide collagenCalf procollagenAchilles tendonIchthyocolIchthyocolIchthyocol gelatinProcollagen gelatinCommercial gelatineCommercial gelatineSpecific reagentH+ TitrationFDNBFDNBFDNBNaOClFDNBGuanidinationGuanidinationTrypsin digestiontitrationD -FructosePh.SO,ClAvailabilityIncomplete64-7050687066668770(%)6050Ref.4849414250515252315354Gallop et ~ 1 .~ ~ 7 56 presented evidence for the presence of ‘ r ester-like ”bonds in collagen which were ruptured when the protein reacted withhydroxylamine in the presence of urea (added to prevent gelation). Theester link was thought to be between the hydroxyl group of hydroxylysineand an adjacent B- or y-carboxyl group of aspartic or glutamic acid, respec-tively, since the reactivity of hydroxylamine was equivalent to the hydroxy-lysine content.Ester Buddecke 57 has recently reviewed this type of link.45F. S. Steven, G. R. Tristram, and I. R. Tyson, Biochem. J., 1961, 80, 4 1 ~ .46F. S. Steven and G. R. Tristram, Biochem. J . , 1962, in the press.47F. S. Steven and G. R. Tristram, Biochem. J., 1962, in the press.48 J. H. Bowes and R. H. Kenten, Biochem. J., 1948, 43, 358.49 C. C. Solomons and J. T. Irving, Nature, 1956, 176, 548.50M. Levy, G. Cabrera, and L. Fishman, Abs. 5th Internat. Congress Biochem.,51M. Levy, L. Fishman, and G. Cabrera, Fed. Proc., 1960, 19, 343.52 J. J. Betheil and P. M . Gallop, Biochim. Biophys. Acta, 1960, 45, 598.53 K. Heyns and M. Rolle, Chem. Ber., 1959, 92, 2451.54 S. Gurin and H. T. Clarke, J . Biol. Chem., 1934, 107, 395.5s P. M. Gallop, S.Seifter, and E. Meilman, Nature, 1959, 183, 1659.56 P. M. Gallop, S. Seifter, M. Lukin, and E. Meilman, J . Anzer. Chem. Xoc., 1960,5 7 E. Buddecke, Angew. Chem., 1960, 72, 663.Moscow, 1961, p. 38 (ref. 2-89-1311).235, 2619374 BIOLOGICAL CHEMISTRYlinkages were demonstrated by Grassmann 57a between carbohydrate residuesand the hydroxyl group of hydroxy-amino-acids.Mechanic and Levy 58 isolated an us-dipeptide of lysine from the partialacid-hydrolysis of Achilles tendon collagen which was found to be N-u-glycyl-N-s-(a-glutamy1)lysine. Joseph and Bose 59 degraded denaturedcollagen with trypsin, which is unable to split peptide bonds adjacent tolysine residues in which the &-amino-groups are involved in chemical linkages.After sodium hypobromite treatment and hydrolysis the amount of succinicacid isolated was equivalent to the amount of y-glutamyl bonds present in theoriginal protein ; in the case of collagen this was 1.3 moles per 105 g., 4-5residues per tropocollagen urut weight.Grassmann et isolated, fromthe tryptic digest of heat-denatured procollagen, peptides which were com-posed of three chains and held together by lateral bonds. It is interestingthat in these experiments about one-third of the bonds adjacent to lysinewere not split by the enzyme as demonstrated by the pH titration duringthe course of the hydrolysis. It would appear that certain types of cross-linkages at the &-amino-groups of lysine have been established beyond doubt,although the quantitative sum of the established cross-links does not ap-proach one-third of the equivalent number of lysine residues which arechemically masked.It is possible that the small amounts of carbohydrate,aldehyde, and nucleic acids already mentioned may contribute to thesubstitution of the lysines. Cross-links have not definitely been proved tobe inter- rather than intra-peptide chain bridges.Chemical studies of the amino-acid sequences of collagen have all re-quired the partial degradation of collagen (by acid or enzyme attack) inorder to provide peptides of suitable length for sequential studies. Specificenzymes excreted by micro-organisms and called collagenases have beenextensively employed in this work (see Mandl 6 0 ) . The collagenases havethe advantage that they will attack native insoluble collagen with thesplitting of peptide bonds to form peptides with N-terminal glycine residues.The main disadvantage of collagenase is that many of the peptides are ofshort length and therefore of little use in the determination of the collagenstructure as a whole.Some longer peptides have however been studiedwith success, notably by Manahan and Mandl,61 Mandl et aZ.,G2 and MichaelsSome of the results of collagenase studies will be discussed in con-nexion with peptides obtained by the action of acid or other enzymes ondenatured collagen. Collagen is remarkably resistant to all enzymes otherthan collagenase when in the native state,60 but swollen or denaturedcollagen is readily attacked by most proteolytic enzymes.Grassmann etaZ.31 digested heat-denatured procollagen with trypsin free from chymotryp-670 W. Grassmann, U. Hofmann, K. Kuhn, H. Hormann, H. Enders, and K. Wolfin “Connective Tissue Symposium,” ed. R. E. Tunbridge et al., Blackwell Press,Oxford, 1957, p. 157.68G. L. Mechanic and M. Levy, J . Amer. Chem. SOC., 1959, 81, 1889.59K. T. Joseph and S. M. Bose, Bull. Central Leather Res. Inst., 1960, 7, 97.$0 I. Mandl, Adv. Enzymol., 1961, 23, 163.61 J. Manahan and I. Mandl, Biochem. Biophys. Res. Comm., 1961, 4, 368.62 I. Mandl, H. Zipper, and L. T. Ferguson, Arch. Bioc7zem., 1958, 74, 465.63 S. Michaels, P. M. Gallop, S. Seifter, and E. Meilman, Biochim. Biophys. Acta,. et ~ 1 . 6 31958, 29, 450TRISTRAM AND STEVEN COLLAGEN 375sin and found only the expected lysine and arginine as C-terminal residues,although not all the expected bonds were split during the reaction (as men-tioned above).The peptides were isolated by continuous curtain electro-phoresis at different pH values, followed by column chromatography onDowex- 1 resins and subsequent paper chromatography. The pure peptidefractions were submitted to total amino-acid analysis as well as sequentialN - and C-terminal analyses. Many of the peptides were composed of threeshort-chain sub-units, cross-linked by unspecified bonds. These hdingsprovide the most convincing chemical evidence in favour of the triple helixstructure of collagen deduced from X-ray a n a l y ~ e s . ~ ~ - ~ ~ Many of the iso-lated peptides were either strongly polar or non-polar in amino-acid dis-tribution which was in excellent agreement with the earlier work 68 fromGrassmann’s laboratory in which these polar and non-polar regions werepredicted from a study of the electron-microscopic analysis of collagen fibrilsin order to account for the inter-band fine structure.The relationshipbetween electron-microscopic and the polar and non-polar regions of collagenhas been confirmed by a study of the collagenase attack on collagen.Collagenase attacks the non-polar regions only. 68a Peptides rich in prolineand hydroxyproline as well as peptides poor in imino-acids were also found,which is in agreement with Manahan and MandLG1 The absence of imino-acids in long peptides suggests that the “ G-P-R ” repeating unit of collagenoriginally proposed by Astbury 69-70 does not extend throughout the wholelength of the collagen molecule.Huggins 71 put forward an alternativestructure in which the imino-acids could be replaced by cyclised residues ofaspartic and glutamic acid and their amides. This modification would notaccount for the ease with which the acidic side-chain groups can be titratedin collagen.48 It is now recognised 72, 7 3 that a considerable part of thetotal imino-acids is present in the sequence “ G-P-R ” in which “ R ” isoften an imino-acid (vix., hydroxyproline). Recent work 74 on a syntheticpolymer of the tripeptide (Gly-Pro-Hypro), with a molecular weight ofca. 25,000 has provided a polymer of known composition which exhibits thetypical X-ray and infrared dichroism pattern associated with native collagen.This would confirm the generally accepted idea that the information obtainedfrom these two types of physical analysis, when applied to collagen, canonly be interpreted with respect to the “ crystalline regions ” of the protein.The “amorphous regions ” do not contribute to the X-ray diffractions4G. N.Ramachandran and G. Kartha, Nature, 1955, 176, 593.65P. M. Cowan, S. McGavin, and A. T. North, Nature, 1955, 176, 1062.s6A. Rich and F. H. C. Crick, Nature, 1955, 176, 915.67 G. N. Ramachandran and V. Sasisekharan, Nature, 1961, 190, 1004.68 W. Grassmann in “ Ciba Foundation Symposium on Chemical Structure ofProteins,” 1953, p. 195.6*aA. Nordwig, H. Hormann, K.Kuhn, and W. Grassmann, 2. physiol. Chem.,1961, 325, 242.BQ W. T. Astbury, J. Internat. SOC. Leather Chem., 1940, 24, 69.7 0 W. T. Astbury and F. 0. Bull, Nature, 1940, 145, 421.71 M. L. Huggins, Proc. Nut. Acad. Sci. U.S.A., 1957, 43, 209.72 R. E. Schrohenloher, J. D. Ogle, and M. A. Logan, J. Biol. Chem., 1959, 234, 58.73M. Nishigai, Y. Nagai, and H. Noda, J. Biochem. (Japan), 1960, 48, 152.74 N. S. Andreeva, V. A. Debabov, M. I. Millionova, V. A. Shibnev, and Y. N.Chirgadze, Biojizika, 1961, 6, 244376 BIOLOGICAL CHEMISTRYpatterns. The isomorphism of the synthetic polypeptide and the " crystal-line regions '' of collagen suggest that these regions were made up to a largeextent of organised sequences of Gly-Pro-Hypro rather than the originalAstbury model of '' G-P-R " in which " R" was not necessarily an imino-acid.The frequency of peptides isolated from partial 75, 76 acid or colla-genase 61, 77 digests of collagen which contain the sequence Gly-Pro-Hyproconfirms the interpretation of these physical studies. Schrohenloher et al.72demonstrated that the high percentage of the total imino-acid contentof collagen was largely contributed by this peptide. The specificity ofcollagenase has been compared on synthetic peptides and procollagenby Grassmann 78 and one of the major requirements for enzyme attackwas found to be P-R-G-P- which was split in the middle with the for-mation of peptides having Gly-Pro or Gly-Hypro at the N-terminal posi-tion. The specificity requirements of collagenase are thus well suitedfor the rupture of bonds associated with the " crystalline regions " of thesubstrate.Kinetic studies on the collagenase digestion of ichthyocol have indicatedtwo configurations 79, 8O of the substrate; below 27" the protein is in theform of a loose polypeptide helix and at higher temperatures exists asrandom coiled chains.Heyns and Legler 81 followed the extent of colla-genase attack on different tissue collagens from within the same animaland from different species by means of the pH-stat and subsequent finger-printing of the peptides liberated. Slight differences in the primary structureof these collagens were observed.Although collagenases are thought to be the only class of proteolyticenzymes which degrade native collagen, other enzymes will attack swollencollagen.60 The most interesting example of this type is the very limiteddigestion by trypsin and chymotrypsin of procollagen dissolved in calciumchloride, described by Hodge et aZ.13 In this digestion about twelve peptidebonds were split per collagen molecule, with the liberation of short peptides,some of which were rich in tyrosine.The resistant core of undigested colla-gen molecule was shown to be incapable of fibre formation. The authorssuggested that the tropocollagen molecules each had short peptide chainsattached to their ends in the form of random coiled tails. In the originaltropocollagen these tails were involved in the end-to-end polymerisationduring fibre formation. The tails were susceptible to trypsin and chymo-trypsin attack since they were in a random-coil configuration whilst theenzyme-resistant core was in the triple-helix form and thus not attackedexcept by collagenase.The presence of tyrosine in these peptides adds76 T. D. Kroner, W. Tabroff, and J. J. McGarr, J. Amer. Chem. SOC., 1953, 75,76T. D. Kroner, W. Tabroff, and J. J. McGarr, J . Amer. Chem. SOC., 1955, 77,77 R. E. Schrohenloher, J. D. Ogle, and M. A. Logan, J . Biol. Chem., 1960,234, 59.W. Grassmann, A. Nordwig, and H. Hormann, 2. phtysiol. Chem., 1961, 323, 48.v 9 W. F. Harrington, P. H. von Hippel, and E. Mihalyi, Biochim. Biophys. Acta,S O P . H. von Hippel and W. F. Harrington, Biochim. Biophys. Acta, 1959, 36,4084.3356.1959, 82, 303.427.K.Heyns and G. Legler, 2. physiol. Chem., 1960, 321, 184TRISTRAM AND STEVEN: COLLAGEN 377strength to their proposed r81e in fibre formation since the amino-acid com-position of collagen is notably deficient in this amino-acid (ca. 1 tyr. per 216residues 3 l ) whilst the tyrosyl residues in collagen have been shown toparticipate in the polymerisation process.82 A study of the tryptic digestionof native soluble collagen has now been reported by Kuhn et aZ.82u whichopposes the findings of Hodge et a L 1 3 Kiihn observed that the trypticdigestion was accompanied by a slight fall in the tyrosine and amino-sugarcontents of the residual protein as compared with the original collagen.The content of all the other amino-acids remained unchanged and it wasclaimed that the enzyme only attacked impurities in the preparation anddid not attack the collagen molecule as such.After enzyme treatment thesoluble collagen was readily converted into the fibrous form. Collagen partlydigested by trypsin a t higher temperatures was still capable of fibrefor mat ion.Gustavson l4 and Mandl 6O both draw attention to the trypsin-pretreat-ment of insoluble collagen which is followed by a fall in the shrinkagetemperature, a characteristic function of insoluble collagens. Smallamounts of peptide material may well have been liberated from the insolublecollagen during enzyme action but escaped notice.14 The non-proteinnitrogen physically attached to collagen and gelatines 45-47 may be relatedto the peptides found by Hodge, which play a part in polymerisation.Partial acid- hydrolysates of collagen and derived gelatines have indi-cated the acid lability of peptide bonds involving glycine, serine, and threo-nine ; these amino-acids appeared most frequently in the N-terminal positionof the resultant peptides.It is worth noting that the predominant N-ter-minal residues of acid-processed gelatines are glycine and, to a much lesserextent, serine and threonine .The present position with regard to the chemical structure of collagenmay be briefly summarised as follows. Soluble collagens are all inter-related in their chemical and physical structures and are the protein inter-mediates of the synthesis and degradation of insoluble tissue collagen.The collagen molecule consists of a triple helical core with peptide chainsattached a t each end which are essential for end-to-end polymerisation.The helix contains organised sequences of the tripeptide Gly-Pro-Hyprowhich are largely responsible for the " crystalline regions " characterisedin X-ray analyses of collagen.Polar and non-polar regions are also foundin the polypeptide chains; these regions are responsible for the interbandh e structure of collagen observed in the electron microscope. Astbury 83has published a fascinating review on the advance in our understanding ofthe collagen molecular structure since the pioneering work of the X-rayanalyses was initiated. A recent review has been published by Rich andCrick ** on collagen structure.The metabolism of collagen and the chemistry of calcification are con-sidered to be beyond the scope of this Report.The metabolism of collagen82 H. B. Bensusan .and A. Scanu, J . Amer. Chem. SOC., 1960, 82, 4990.88 W. T. Astbury, J . Internat. SOC. Leather Chem-., 1960, 45, 186.84A. Rich and F. H. C. Crick, J . Mol. Biol., 1961, 3, 483.K. Kuhn, J. Kiihn, and K. Hannig, 2. physiol. Chem., 1961, 328, 60378 BIOLOGICAL CHEMISTRYhas been extensively investigated 12, 85-g1 and is described elsewhere; calci-fication has been well reviewed by Glimcher g2 and other aufhor~.*3, 939 94G. R. T.F. S. S.3. TRYPTOPHAN METABOLISMMOST of the work on ommochromes has been published in German, and therehave been no recent reviews in English. Rapid progress is being made inthe elucidation of the structures of various ommochromes, but the mostsignificant contribution made by these studies to biological science is yrob-ably in genetics.This early work on Drosophila and Ephestia mutants hasbeen reviewed in English ;l it gave the first indication that genes may expressthemselves phenotypically by exerting control over the synthesis of specificenzymes. The recent studies on the genetics of tryptophan biosynthesisare a good illustration of the development in our understanding of the geneenzyme relationship since the genetic control of enzyme synthesis was firstsuggested.0mmochromes.-The ommochromes are a class of natural pigmentswhich contain the phenoxazine ring system. They are especially commonin, but not limited to, the Arthropoda, and were named from their occurrencein the ommatidia of the insect compound eye.2 Becker divided them intotwo groups: those of low molecular weight, alkali-labile ommatines; andthose of high molecular weight, alkali-stable ommines.I n uiuo they areoften bound to protein as chromoprotein granules. Their insolubility inneutral solvents and the instability of some of them towards acid or alkalihas made isolation and purification difficult. Nevertheless, since their firstreport on the purification of xanthommatine, Butenandt et al. have publishedit series of elegant studies on the chemistry and biochemistry of thesecompounds.Three ommatines and one ommine have now been isolated and studied.Recently described column separations on Perlon powder and on ion-exchange cellulose have greatly facilitated the purification of the om-matines.3 Perlon has the advantage of high capacity; up to 1 g.‘of crudeommatines could be separated on a 6 x 50 cm. column. Xanthommatine (1)was eluted with O-O66~-phosphate (pH 7.0), then rhodommatine (3) withworths Scientifk Publns., London, 1953, p. 140.85 S. F. Jackson in “ Nature and Structure of Collagen,” ed. J. T. Randall, Butter-88 F. M. Sinex, D. D. van Slyke, and D. R. Christman, J . Biol. Chem., 1959,234,918.8 7 R. D. Harkness and B. E. Moralee, J . Physiol., 1956, 132, 502.8sE. Hausmann and W. F. Neuman, J . Biol. Chem., 1961, 236, 149.89G. B. Gerber and K. I. Altman, Nature, 1961, 189, 813.9oR. J. Boucek and N.L. Noble, Biochem. J., 1961, 80, 148.9lD. S. Jackson and J. P. Bentley, J . BiOPhy5. Biochem. Cytol., 1960, 7 , 37.92 M. J. Glimcher in “ Connective Tissue, Thrombosis, and Atheroschlerosis,”93B. N. Bachra and A. E. Sobel, Arch. Biochem., 1959, 85, 9.94K. A. Piez, M. S. Lewis, G. R. Martin, and J. Gross, Biochim. Biophys. Acta,lA. Butenandt, Endeavour, 1952, 11, 188.2E. Becker, 2. Vererbungslehre, 1942, 80, 157.3A. Butenrtndt, E. Biekert, H. Kubler, and B. Linzen, 2. physiol. Chem., 1960,ed. I. H. Page, Academic Press, New York, 1959, p. 97.1961, 53, 596.319, 238SCOTT: TRYPTOPHAN METABOLISM 3791M-pyridine acetate (pH 6-5), and ommatine D with ZM-pyridine gcetate(pH 7-0).Very small amounts of rhodommatine and ommatine D (<5 pg.) couldbe separated and quantitatively recovered on “ ecteola ” cellulose with3M-pyridine acetate.Xanthommatine was rapidly destroyed in thissolvent, but 65% recoveries were achieved by the addition of small amountsof dithionite.The structure of xanthommatine was confirmed by synthesis in 1954.4It exhibits marked redox behaviour. Xanthommatine (1) (yellow) isreduced by sulphur dioxide or dithionite to dihydroxanthommatine (2)(red) which is autoxidisable in air. This redox behaviour is not shown byrhodommatine (3) or ommatine D (4), whose oxidation state is equivalentto that of dihydroxanthommatine ; the reduced phenoxazone ring system isstabibed against autoxidation by the attachment of a glucose residue asin (3) or a sulphate group as in (4).The position of the sulphate in ommatineD has been confirmed by synthesis from dihydroxanthommatine wia its tri-sodium salt (Q5 The position of the glucose residue in rhodommatine isC02HICH’NHIIco2nIICH.NH2CO2HIR= G I uc as y I4 A. Butenandt, U. Schiedt, E. Biekert, and R. J. T. Cromartie, 2. physiol. Chem.,6 A. Butenandt, E. Biekert, N. Koga, and P. Traub, 2. physiol. Chem., 1960, 321,1954, 590, 75.258380 BIOLOGICAL CHEMISTRYCOzNa CO. 0. SO 3HI ICH.NH2 CH.NH2I ICH2I0(1) - 0Reagents: (1) Na,S,O,-NaOH. (2) Cl*SO,H. (3) +2H,O.uncertain.s Both the N-glucoside (3b) and the O-glucoside (3a) are possiblein molecular models, and N - and 0-glucosyl derivatives are both known tooccur in insects.Purification of crude ommine was at first difXcult.7 Ommine is sostrongly adsorbed by aluminium oxide that it is only incompletely eluted bythe strongest eluants, such as formic acid-hydrochloric acid-methanol. Itis even strongly adsorbed by cellulose powder or talc.Partition chromat-ography on kieselguhr with aqueous phenol resulted in extensive decomposi-tion of the ommine. Paper electrophoresis was also impossible because ofstrong adsorption.Ommine mixtures from the eyes of B d y z mi, Cragnon vulgaris, andSepia oficianalis have now been separated by preparative circular chromato-graphy in collidinewater (3 : 1).8 They all contain about 75% of the sameviolet-black component which has been named ommine A. Ommine A ex-hibits characteristic redox behaviour : a red-violet solution in methanolichydrochloric acid becomes yellow during 14 days in air.Hydrogen per-oxide or sodium nitrite performs the oxidation in a few seconds. Thereduced form is regenerated by heating the yellow form with sulphur dioxide.Degradation studies on ommine A suggest the structure (6), a tribenzo-oxazine-thiazine system with three free a-amino-y-oxo-carboxylic acid sidechains. Synthetic compounds with this chromophore have similar ultra-violet spectra to that of ommine A. Reduced, red-violet ommine A canonly be oxidised in acid solution, which would be expected of structure (6) ;6 A. Butenandt, Report of XVIIth Internet. Congress Pure Appl. Chem., Munich,' A . Butenandt, E. Biekert, and B. Linzen, 2. physiol.Chem., 1958, 312, 227.s A . Butenandt, G. Neubert, and U. Baumann, 2. physiot. Chem., 1959, 314, 15.1960, Verlag Chemie, Weinheim/Bergstr., p. 11SCOTT : TRYPTOPHAN METABOLISM 381an " onium salt " can be formed, which represents the " amino-diacyl-phenoxaxine " ; structure (7) is necessary for the characteristic colour change.Genetic and microchemical studies showed that insect-eyepigments are derived biologically from tryptophan (8) via N-formyl-kynurenine (9), kynurenine (lo), and 3-hydroxykynurenine (11). Thiswas confirmed later by the incorporation of labelled intermediates intoommochromes. [#?- l4CITryptophan and [ Wlkynurenine (labelled on thecarbonyl group of the side chain), injected into the larvae of Vanessa urticz,were incorporated into xanthommatine and rhodommatine in the post-pupalsecretion of the imago.g [P-l%] Tryptophan, injected into the pupae of'Calliphora erythrocephakc, was incorporated into xanthommatine in the eyesof the imago.10 Labelled tryptophan was also incorporated into omminein Bombyx m ~ r i .~Body fluid from wild strains of Bombyx rapidly forms melanin andblackens on exposure to air. Under the same conditions, body fluid froma mutant rb, which contained unusually high levels of 3-hydroxykynurenine,became red.ll Inagami demonstrated the production of " red melanin "in vitro by the action of tyrosinase on a mixture of 3-hydroxykynurenine anddihydroxyphenylalanine (dopa) (12). This product must have been a mix-ture of melanin and xanthommatine; Butenandt et al.demonstrated thesynthesis of xanthommatine and dopa-melanin in vitro by the action ofCalliphora-tyrosinase on a mixture of 3-hydroxykynurenine and d0pa.l3-Hydroxykynurenine alone is not oxidised by tyrosinase, and small amountsof dopa must be present for xanthommatine synthesis. The oxidation of3-hydroxykynurenine can thus be coupled with the redox system, dopa (12) + dopaquinone (13). Synthesis of xanthommatine in vivo may involve aBiosynthesis.similar mechanism. Yoshi and Brown,13 however, reported the synthesisof xanthommatine from 3-hydroxykynurenine by rat-liver mitochondriawith added cytochrome c. The oxidation was inhibited by cyanide ion anddid not require DPN, TPN, or FAD. Since mammals can synthesise3-hydroxykynurenine from tryptophan, the mammalian biosynthesis ofxanthommatine is a possibility.sA. Butenandt and R.Beckmann, 2. physiol. Chem., 1955, 301, 115.loA. Butenandt and G. Neubert, 2. physiol. Chem., 1955, 301, 109.l1 K. Inagami, Nature, 1954, 174, 1105.12A. Butenandt, E. Biekert, and B. Linzen, 2. physiol. Chem., 1956, 305, 283.I3S. Yoshi and R. R. Brown, Fed. Proc., 1959, 18, 255382 BIOLOGICAL CHEMISTRY402 4 12The pre-pupal secretions of some Lepidoptera contain ommatines whichare synthesised in the Malphigian tubules. Their histogenesis has beenstudied in Ptychopoda seriata and Ephestia Euhniellu.l4A study of the natural distribution of ommine wascarried out before the separation of crude ommine had been achieved.15'' Ommine " was characterised by: (1) Paper chromatography (one spot,RF 0.7 in formic acid-methanol-hydrochloric acid, 15 : 3 : 1).(2) Ultra-violet spectra (typical absorption bands are given in concentrated sulphuricacid; there is a typical maximum at 520 mp in buffer of pH 7.5, which isreplaced by a weaker band at 530 mp in 5~-hydrochloric acid). (3) Infraredspectra (owing to the many polar forms, the infrared spectra of the ommo-chromes show fairly wide bands with little finer structure, but they can beused for identification).Ommine was found in all investigated orders of the Insecta and Crustucea.It is an especially common eye pigment in crabs, spiders, insects, andcephalopods, and is also present in the epidermis of Cragnon, Limulus, andGyllus, but not in Carcinus and Portunus.Ommine is present in the eyes and skin, but not in the ink, of Sepianficianalis (Cephalopoda).lG, Xanthommatine has been identified in theeggs of the marine worm Urechis caupo (Echiurid~).l' No ommochromeswere found in Chlamys ~perularis.~ Human red hair, the feathers of RhodeIsland fowls, and the urine of alcapturonics do not contain ommochromes.3The violet pigment of the fish Lepohgaster gouani could not be identifiedwith any known omm~chrome.~ Butenandt et aZ.3 have reported the distri-bution of ommatines in a large number of arthropods, especially insects.Xanthommatine was found in very small amounts, together with ommine,in some crustaceans.It was present in the integument of Asellus aquaticus,in the eyes of Leander serratus, and probably in the eyes of Ligia oceana,Neomysis integer, and Porcello amber.Xanthommatine was found universally in insects as an eye pigment,accompanied in most orders by a greater amount of ommine.In the eyesl4 R. Wolfram, 2. Vererbungslehre, 1949, 83, 254.15A. Butenandt, E. Biekert, and B. Linzen, 2. physiol. Chem., 1958, 313, 251.16 I. Schwink, Natumoiss., 1953, 40, 365.l7B. Linzen, 2. physwl. Chem., 1959, 314, 12.Natural occuwenceSCOTT : TRYPTOPHAN METABOLISM 383of many of the Diptera (Calliphora erythrocephula, Syrphw pyrmth, Muscadomestim, Drosophila melanogaster), however, xanthommatine wans the onlyommochrome. Rhodommatine and ommatine D were only found in theLepidoptera. They are present in the wings of the Nymphalida, wherethey contribute greatly to the pigmentation, but are absent from the eyesand all other ectodermal structures.They are also present in the post-pupal secretions as their water-soluble ammonium salts ; indeed, the firstisolates were made from this source.It was onlyfound when the amount of ommatine D was decreased by storage. About20 pg. of ommatine D and 5 pg. of rhodommatine are present in the wings ofone specimen of Vanessa urticai?. Ommatine D also predominates in thewings of other Nymphalidae. Xanthommatine was the only ommochromefound in the epidermis of 1arvE and pupaThe large amounts of xanthommatine previously found in post-pupalsecretions were derived from ommatine D, and it is doubtful whetherxanthommatine occurs in fresh secretions.Ommatines of the post-pupal secretion are synthesised just before pupa-tion, and are localised in the alimentary canal.In Cerura vinula they arealso synthesised in large quantities in the fat body. They are absent fromthe gut of pup% and larvz of those species which produce post-pupal secre-tions which lack ommatines (Sphinx pinastri, Bupalus piniarius).Biosynthesis of Tryptophan.-The conversion of indole into tryptophanby micro-organisms was first indicated by Fildes,18 who showed that trypto-phan-requiring strains of Bact. typhosum, C. diphtheriai?, and Staphylococcuswould grow in the absence of tryptophan if indole was present. Snell l9obtained the same results with L. arabinosus and L. casei, and showed thatthe tryptophan requirement can also be satisfied by anthranilic acid in theseorganisms.The participation of anthranilic acid and indole in the biosyn-thesis of tryptophan was confirmed in Neurospora crassa and Escherichia co2iby studies with auxotrophs and by isotope incorporation studies.20, 21, 22Uniformly labelled indole is converted into tryptophan without dilution bytryptophan auxotrophs of E. coli and Bacillus s ~ b t i l i s . ~ ~ Isotope tracerstudies on the synthesis of indole from anthranilic acid showed that thecarboxyl carbon of anthranilic acid (14) is lost during the conversion inNeurospora and E. C O Z ~ , ~ ~ , 25 that the two carbons of the pyrrole ring arederived from C(l) and C(z) of a ribose derivative in E . ~ o l i , ~ ~ and that theamino-nitrogen of anthranilic acid is retained as the pyrrole nitrogen inNeurospora.26It is doubtful whether xanthommatine occurs in wings.l8 P.Fildes, Brit. J. Exp. Path., 1940, 21, 315.Is E. Snell, Arch. Biochem., 1943, 2, 389.2o E. L. Tatum, D. M. Bonner, and G. W. Beadle, Arch. Biochem., 1943-44,3, 477.21E. L. Tatum and D. M. Bonner, J . Biol. Chem., 1943, 151, 349.22 C. Yanofsky, in W. D. McElroy and B. Glass, " Amino-acid Metabolism," Balti-23C. Yanofsky, J. Bact., 1954, 68, 577.24 J. F. Nyc, H. I(. Mitchell, E. Leifer, and W. H. Langham, J. Bwl. Gh., 1949,25 C. Yanofsky, J. Biol. Ghem., 1955, 217, 345.26 C. W. R. Partridge, D. M. Bonner, and C. Yanofsky, J. Bwl. Chem., 1952, 194,more, 1955, p. 930.179, 783.269384 BIOLOGICAL CHEMISTRYA cell-free extract of E .coli, which converts anthranilic acid into indole,was separated by ammonium sulphate precipitation into two protein frac-tions (A and B).27 Fraction A catalyses the conversion of anthranilic acidinto 3-C-(3-indolyl)glycerol 1 -phosphate (18) by reaction with 5-phospho-ribosyl 1-pyrophosphate (15) in the presence of Mg2 +. Fraction B effects thecleavage of indolylglycerol phosphate to indole (19) and glycerol phosphate(20). The mecha,nism of this conversion has not been unequivocally proved.By analogy with other reactions of phosphoribosyl pyrophosphate, forma-tion of the anthranilic acid ribotide (16) is suggested as the first step. A re-action similar to an Amadori rearrangement would convert (16) into the1 -deoxy-2-oxo-intermediate which, in the enol form (17), could cyclise ;decarboxylation would then give indolylglycerol phosphate.? ? r--0-f HO - 7 - 0-7 - 0- C- $H -CH- 4.CH 2.0.PO 3H 2OH OH OH OH HHE . coli suspensions also convert 4-methylanthranilic acid into an indolederivative. If ring closure in 4-methylanthranilic acid (21) occurred atposition 1 on the aromatic ping, the product would be 6-methylindole (22).Closure at position 3 would give 4-methylindole (23). The indole derivativewas identified as 6-n1ethylindole.~2 Thus ring closure occurs at the carbonatom with the attached carboxyl group. This also supports the assumption2' C. Yanofsky, J . Biol. Ch.em., 1956, 223, 171SCOTT : TRYPTOPHAN METABOLISM 385that cyclisation occurs before decarboxylation.If decarboxylation were thefirst step, a mixture of 4-methylindole and 6-methylindole would be expectedfrom 4-methylanthranilic acid.Condensation of indole with serine (24) to give tryptophan was suggestedby studies on Neurospora whole mycelium. 28 Cell-free preparations ofNeurospora were then shown to catalyse this reaction, and a requirementfor pyridoxal phosphate was demonstrated.29 The enzyme has been purified12-20-fold from Neurospora and has a pH optimum of 7+3.30 It is assayedby following the disappearance of indole from reaction mixtures containingpyridoxal phosphate and high concentrations of indole and serine.30 Theenzyme has been called tryptophan desmolase,3l tryptophan sy~ifhetase,~~and tryptophan d e ~ m a s e .~ ~ - (8)The rate of synthesis of tryptophan from indolylglycerol phosphate irLNeurospora preparations is far higher than the rate of formation of indolefrom indolylglycerol phosphate. Furthermore, free indole could not betrapped in toluene during the above ~ynthesis.3~ It was therefore suggestedthat tryptophan synthetase catalyses reactions (1)-(3) where reaction (2)Indole + L-Serine + L-Tryptophan (1)L-Tryptophan + Triose phosphate (2)Indolylglycerol phosphate + Indole + Triose phosphate (3)is not the sum of reactions (1) and (31, and is the most important in thewild strain under normal growth conditions (no indole or tryptophansupplements). This is supported by the finding that indolylglycerol or asimilar compound is accumulated by Neurospora mutants which lacktryptophan synthetase, and no Neurospora mutant has been discoveredwhich responds t o indole and accumulates indolylglycerol.28 E.L. Tatum and D. M. Bonner, Proc. Nut. Acud. Sci. U.S.A., 1944, 30, 30.2 9 W. W. Umbreit, W. A. Wood, and I. C. Gunsalus, J . Biol. Chem., 1946, 165, 731.3 0 C . Yanofsky, J . Biol. Chern., 1952, 194, 279.31 M. Gordon and H. K. Mitchell, C;yeticS, 1950, 35, 110.32 S. P. Colowick and N. 0. Kaplan,53 J. Rlonod and G. Cohen-Bazire, Conapt. rend., 1953, 236, 530.34 C. Yanofsky and M. Rachmeler, Biochinz. Biophys. -4cta, 1958, 28, 640.Indolylglycerol phosphate + L-Serine +Method in Enzymology,” Academic PressInc., New York, 1955, Vol. 11, p. 233.386 BIOLOGICAL CHEMISTRYSome auxotrophs of E .coli and Neurospora, which lack tryptophabsynthetase, contain a protein (designated CRM) , which is immunologicallysimilar to the 36, 37 Other tryptophan auxotrophs of bothorganisms do not form detectable amounts of tryptophan synthetase orCRM. In E. COG, all auxotrophs lacking CRM and tryptophan synthetasealso lack an enzyme called component B which is necessary for the conver-sion of indolylglycerol phosphate into i n d ~ l e . ~ ~ Mutations of this type areclue to one mutational event. This was difEcult to explain on the basis ofthe " one gene one enzyme " concept, until it was shown that component Band tryptophan synthetase activity are normally associated with the sameprotein, and both participate in the conversion of indolylglycerol phosphateinto indole, and the conversion of indole into tryptophan.CRM is a muta-t ionally altered form of tryptophan synthetase. 39Tryptophan synthetase from E. coli can be separated into two proteinfractions (A and B). Each fraction alone is inactive in reactions (l), (2),and (3), but a mixture of A and B has all the catalytic properties of trypto-phan synthetase. Component A is slightly active in reaction (3) and com-ponent B in reaction (l), but in neither case is the activity more than 10% ofthat for a mixture of the two components. Component B is unstable inthe absence of pyridoxal phosphate. Each component was assayed by theusual method for tryptophan synthetase in the presence of an excess of theother component.This interesting separation of an enzyme into two inactive proteins wasperformed on diethylaminoethylcellulose with a sodium chloride gradientin phosphate buffer, and is the first of its kind to be reported.40 In theabsence of component B, a single peak of protein A appears in the earlyfractions.When B is present, however, there is a biphasic distribution;a portion of protein A stays in combination with B and is eluted later.Considerable evidence now indicates that genes controlling related bio-chemical reactions are situated close to each other on the chromosomes.41~ 42A great contribution to this aspect of biochemical genetics has recently beenmade by studies on tryptophan biosynthesis. Bacteriophage can act as acarrier of genetic characters from one bacterial strain to another. In thisprocess, called transduction, all closely linked characters can be transferredtogether, which indicates that their corresponding genes can be carried bythe same phage particle.Thus several genes which control related bio-chemical reactions may be " clustered " on the bacterial chromosome.Moreover, there is substantial evidence that genes controlling the variousintermediate biosynthetic reactions are arranged in the same order as thebiochemical steps they control.431355, 41, 577.35 S. R. Suskind, C. Yanofsky, and D. 31. Bonner, Proc. Nut. Acad. Aci. U.S.A.,3 6 s . R. Suskind, J . Bact., 1957, 74, 308.a 7 P . Lerner and C. Yanofsky, J . Bact., 1957, 74, 494.38 C. Yanofsky and 3. Stadler, Proc. Nut.Acad. Sci. U.S.A., 1958, 44, 245.39 C. Yanofsky, Biochim. Biophys. Acta, 1959, 31, 408.40 I. P. Crawford and C. Yanofsky, Proc. Nut. Acad. Sci. U.S.A., 1958, 44, 1161.41P. E. Hartman, Carnegie Inst. Wash. Publ. NO. 612, 1956, p. 35.4zM. Demerec and Z. Hartman, Carnegie Inst. Wash. Publ. NO. 612, 1956, p. 5 .43 E. S. Lennox, Virology, 1955, 1, 190SCOTT TRYPTOPHAN METABOLISM 387Phage P-1 has been used to transduce characters between mutant strainsof E . coli K12.44 A typical transduction was performed as follows: A strainblocked in the synthesis of anthranilic acid (tryp 4) was infected with phage,and the lysed culture treated with toluene to ensure the death of any sur-viving cells. The phage from this lysate was then used to infect a mutantblocked in the conversion of indolylglycerol phosphate into tryptophan(tryp 1).After plating out on a medium supplemented with anthranilicacid, those strains with no block between anthranilic acid and tryptophanwere the only ones able to grow. There are two possible types, (tryp 41-tryp 1 +) and (tryp 4- tryp 1 +), and these can be distinguished nutritionally.The frequency with which the donor characters tryp 4- and tryp I f aretransduced together is a measure of the degree of linkage (proximity on thebacterial chromosome) of these two. Similar transductions between differ-ent mutant pairs showed that the probable order of genes is tryp 4, tryp 3,(tryp 2, tryp 1). Tryp 1 and 2 appeared so close by this mapping methodthat their relative order was uncertain.Use of double mutants, however,made the sequence tryp 4, tryp 3, tryp 1, tryp 2 most probable. Transduc-tion studies with similar auxotrophs of Salmonella typhimurium showed thesequence, tryp 4, tryp 3, tryp 2, tryp l.42 By transduction it has also beenpossible to map the relative positions of different mutational sites within thesame functional unit,44 e.g., tryp 1-1, tryp 1-2, tryp 1-3. These investiga-tions have been extended to a detailed study of the genetic locus whichcontrols the synthesis of enzymes acting between indolylglycerol phosphateand tryptophan in E. coli, i.e., mutations which affect components A and Bof tryptophan ~ynthetase.~5Four different mutants for component A (A-1, A-2, A-3, A-4) have beenisolated and each altered site mapped by transduction.All four sites werelocated in one small region of the chromosome. Mutants A-1 and A-3formed a protein which catalysed reaction (l), but no others. A-2 and A-4formed no material with A activity in any of the three reactions. Immuno-logical tests showed that A-2 and A-4 form no A-CRM, but A-CRM wasdetected in A-1 and A-3. All four mutants produced normal component B.Six different mutations in the B region of the genetic material weredetected. Three of these resulted in the accumulation of indole, and threein the accumulation of indolylglycerol. The indole-producing mutantsformed a B-CRM, which was active in reaction (3), but not in (1) and (2)The indolylglycerol producers formed no B-CRM and had no compodent Bactivity in any reaction.All six B mutants produced normal component A.44C. Yanofsky and E. S . Lennox, Virology, 1959, 8, 425.45 C. Yanofsky and I. P. Crawford, Proc. Nat. Acad. Sci. U.S.A., 1959, 45, 1016388 BIOLOGICAL CHEMISTRYTransduction studies showed the sequence, B-4, B-6, B-2, B-5, B-1, B-3,A possible interpretation of these A and B mutations, based on theWatson-Crick DNA has been put forward.45 Loss of the abilityto form any ,4 or B protein could represent “ nonsense ” mutations, i.e.,a nucleotide substitution in DNA, which prevents the incorporation of anamino-acid, so that an incomplete or no polypeptide chain is formed. Syn-thesis of CRM-type proteins would represent a nucleotide substitution whichdoes not prevent the synthesis of the protein molecule, but leads to a differentcoding sequence, with respect to a single amino-acid.Suppressor mutation has also been studied in tryptophan biosynthesis.47Suppressor mutations reverse the effect of a primary mutation, and theyoccur at a genetic locus distinct from the site of the primary mutation.They may permit the synthesis of an essential compound by an alternativepathway, or they may reduce the level of an inhibitor to which an enzymehas become sensitive by a primary mutation.48, 49, 50 Two mutants ofE. coli, which lack a specific tryptophan synthetase or any protein immuno-logically related to it, can produce a protein with wild-type activity bysuppressor mut’ati0n.~1 In Neurosporu, mutants with an altered tryptophansynthetase (CRM) simultaneously attain normal enzyme activity and losethe altered protein by suppre~sion.~~A new mode of action of suppressor mutations has now been illustratedin tryptophan auxotrophs of Neurospora: and E.coli; suppression permitsthe synthesis of a second enzyme (in addition to the CRM) with the samecatalytic properties as the wild-type enzyme.In certain E. coli mutants with defective A protein, suppression givesrise to a new protein with A activity, but the A-CRM is still present. Thenew enzyme shows a slightly poorer affinity for component B than does itswild counterpart, but is otherwise chromatographically and catalyticallysimilar to wild type A. Crawford and Yanofsky 47 consider that the sup-pressor gene probably acts by modifying a small amount of the CRMmaterial.If normal and mutationally altered A differ only slightly, it ispossible that a short amino-acid sequence, similar to that in the affectedarea of A, might be exchanged with the altered region in the CRM moleculeto give a small qmntity of active enzyme. It is not known at which stagein protein synthesis such a transpeptidation could occur.The control of tryptophan synthesis by enzyme repression has beenstudied in Aerobucter 33 and more recently in Neurosporu 53 and E. COW** 55A 34-fold decrease in the tryptophan synthetase activity of whole cellsA-2, A-4, A-3, A-1.46 F. H. C. Crick, Symposia of the Society for Experimental Biology, 1958, 138, 12.4 7 1 . P. Crawford and C. Yanofsky, Proc.Nut. Acad. Sci. U.S.A., 1959, 45, 1280.48 S. R. Suskind and L. I. Kurek, Proc. Nut. Acad. Sci. U.S.A., 1959, 45, 193.49 J. Lein and P. S. Lein, Proc. Nut. Acad. Sci. U.S.A., 1952, 38, 44.S. Strauss and S. Pierog, J . Ben. Microbiol., 1954, 10, 221.51 C. Yanofsky, Science, 1958, 128, 843.52 C. Yanofsky, in “ Enzymes, Units of Biological Structure and Function,’’ ed.0. H. Goebler, Academic Press, New York, 1956, p. 147.53 G. Lester, J . Bact., 1961, 81, 964.saG. Lester and C. Yanofsky, J . Bact., 1961, 81, 81.55 T. A. Scott and F. C. Happold, Biochem. J . , 1962, 82, 407GOODWIN : BIOSYNTHESIS OF TEIAMINE 389of Aerobucter was effected by growth in the presence of O-OO5M-L-trypto-pham33 The formation of tryptophan synthetase in Neurospora is prob-ably subject to repression by tryptophan; in a tryptophan-dependent strain(blocked in the synthesis of indolylglycerol phosphate), the tryptophansynthetase activity was inversely proportional to the tryptophan concentra-tion of the germination medium, but the highest and lowest activity onlydiffered by a factor of three. No such effect was observed in a tryptophan-independent strain, but in this case there was a marked repression of theanthranilic acid synthesising system. Thus, in wild type Neurospora, thetryptophan-synthetase step does not seem to be an effective point for theregulation of tryptophan synthesis.6-Met hyltryptophan, 5-met hyl-tryptophan, and especially indolylacetic acid caused a 2-3-fold stimulationof tryptophan synthetase formation.6-Methyltryptophan probably actsby inhibiting the synthesis of anthranilic acid, but the other two inhibitneither anthranilic acid nor indole synthesis. 53In E. C O Z ~ , ~ ~ , 55 tryptophan synthetase is repressed by tryptophan andis stimulated by anthranilic or 3-methylanthranilic acid. 54 This stimu-latory effect is thought to be due to an inhibition of the conversion ofanthranilic acid ribotide into indolylglycerol phosphate, causing a decreasein the level of free intracellular tryptophan. These conditions are theconverse of those obtaining in enzyme repression.T. A. S.4. BIOSYNTHESIS OF THIAMINE AND RELATED COMPOUNDSAPART from being universally required by animals, thiamine (1) is also anessential growth factor for many micro-organisms, and it was investigationson micro-organisms which yielded the first clues to the pathway involvedNH,in its biosynthesis.andof Robbins and Kavanagh 2 on the mould Phycomyces blakeskeanus showedthat, although it was reputed to require thiamine for growth, this require-ment could also be met by a mixture of 5-( 2-hydroxyethyl)-4-methylthiazoleThe now classical work of Schopfer and Jung(2) and 4-amino-5-hydroxymethyl-2-methylpyrimidine (3), both com-ponents of the parent compound. After these observations, many morethiamine-requiring fungi were examined 37 and it was found that theycould be divided into four categories according to whether they requiredI W. H. Schopfer and A. Jung, Compt. rend. Acad. Sci. U . R.S.S., 1937, 204, 1500W.J. Robbins and F. Kavanagh, Proc. Nut. Acad. Sci. U.S.A., 1937, 23, 499.W. H. Schopfer, Phnts and Vitamins, Chronica Botanica, Waltham, 1943.E. L. Tatum and T. T. Bell, Amer. J. Bot., 1946, 33, 362390 BIOLOGICAL CHEMISTRY(a) preformed thiamine, (b) both components (2) and (3) preformed, (c) only(2) preformed, or (d) only ( 3 ) preformed. Similar results were obtained withbacteria which require thiamine for gr0wth,3 although most bacteria do notneed thiamine as a growth factor. These nutritional experiments clearlyindicated that the final stage in thiamine biosynthesis was the condensationof compound (2) with (3); however, the direct demonstration of this at theenzyme level has only recently been achieved.Thefirst direct demonstration that compound (2) was incorporated into thiaminewas made by Korte and his colleagues 5 who showed that when the [2-I4C]-compound (2) was added to cultures of various fungi, label appeared inthiamine; [2-14C]-4-methylthiazole (4), on the other hand, was not incor-porated. Similar experiments with 4-amino-5-aminomethyl-2-[ l4CImethyl-pyrimidine (5) resulted in labelled thiamine irrespective of whether themicro-organisms used did not require thiamine for growth or fell into oneof the classes enumerated above.It is extremely doubtful whether com-Mechanism of condensation of pyrimidine and thiaxole fragments.pound (5) is incorporated intact into thiamine as such; indeed, recentenzymic studies with yeast extracts have demonstrated its conversion intothe hydroxymethyl analogue (3) before incorporation into thiamine.gfound that condensation of the thiamine “ com-ponents ” (2) and (3) to form thiamine by crude extracts of baker’s yeastrequired ATP, but that the ATP requirement was abolished if the phosphateester (Py-P) was substituted for the alcohol (3).However, using purerenzyme preparations, Leder 8 showed that ATP was still required even inthe presence of Py-P and that the first product of the reaction was thiamineHarris and Yavit(6)monophosphate (6). These observations led eventually to the elucidation ofthe mechanism of the series of reactions (1)-( 5) by a number of investigatorsalmost simultaneously.5 F. Korte and H. Weitkamp, Annakn, 1959, 622, 121; F. Korte, H. WeitkampG.W. Camiener and G. M. Brown, J . Biol. Chem., 1960, 235, 2404.7D. L. Harris and J. Yavit, Fed. Proc., 1957, 16, 192.*I. G. Leder, Fed,. Proc., 1959, 18, 270.9 I. G. Leder, Biochem. Biophys. Res. Comm., 1959, 1, 63; G. W. Camiener andG. M. Brown, J . Amer. Chem. Soc., 1969, 81, 3800; J . Biol. Chem., 1960, W, 2411;Y. Nose, K. Ueda, and T. Kawasaki, Biochim. Biophys. Acta, 1959,34,277; J. Suzuokiand A. Kobata, J . Biochem. (Japan), 1960, 47, 262; L. M. Lewin and G. M. Brown,Fed. Proc., 1961, 20, 447; J . BWZ. Chem., 1961, 236, 2768.and J. Vogel, ibid., 1959, 628, 158GOODWIN BIOSYNTHESIS O F THIAMINE 3914-Amino- 5-hydroxymethyl-2-methylpyrimidine + ATP +4-Amino-2-methyl-5-phosphatomethylpyrimidine (Py-P) + ADP (1)Mg’+Py-P + ATP --+ Py-P-P + ADP (21Mgt *5(2-Hydroxyethyl)-4-methylthiazoIe + ATP --t4-Methyl-5(2-phosphatoethyl)thiazole (Th-P) + ADP (3)Mg2+Py-P-P + Th-P Thiamine monophosphate f P-P (4)Thiamine monophosphate + H,O + Thiamine + Pi (5)The separation of the synthesis of Py-P-P into two stages has beenindicated by the following observations of Lewin and (a) duringthe reaction Py-P always appears first ; ( b ) a purified enzyme converts Py-Pinto Py-P-P without the intermediate formation of the free pyrimidine;(c) the activity of a Py-P-P forming enzyme can be destroyed withoutaffecting reaction (1) ; ( d ) UTP, GTP, or CTP can replace ATP in maction (1)but not in reaction (2); and (e) reaction (2) requires a metal ion (Mg2+ orMn2+) whilst reaction (1) doesAlthough the details of reaction (3) are not completely settled, it prob-ably takes place as indicated, because the thiazole pyrophosphate has nevorbeen detected during the reaction.The enzyme carrying out reaction (4), thiamine monophosphate syn-thetase, or thiamine phosphate phosphorylase, is specific for the two sub-strates indicated.The pyrimidine component (3) ofthiamine differs from the pyrimidines found in ribonucleic acid (RNA) anddeoxyribonucleic acid (DNA) in one important respect; it has a 2-methylsubstituent. The 5-hydroxymethyl substituent can also be consideredunique in the present context because such a substituent is only found incertain special DNA molecules,lO such as in bacteriophage T,.As certainmicro-organisms require the preformed pyrimidine residue of thiamine, andas they must certainly be able to synthesize their nucleic acid pyrimidines,it is clear that the requirement for the thiamine pyrimidine (3) is the resultof either (a) a pathway of synthesis different from the conventional one,1°( b ) the inability of the organism to insert the required substituent at posi-tion 2 and/or 5, or (c) the inability of the organism to remove the ribose5-phosphate from, for example, uridine 5’-phosphate, because pyrimidinesare synthesized at the nucleoside 5’-phosphate level whilst, as we have justreported, the free pyrimidine is the mandatory substrate for thiaminebiosynthesis.The problem of the synthesis of the pyrimidine residue of thiamine isnow ripe for direct biochemical attack but at the time of writing very littlework has been reported.Pine and Guthrie11 found that Bact. subtitis(ATCC 6051) incorporates [l*C]formate specifically into the pyrimidine frag-ment of thiamine. As formate is not a component of the ring system ofFormation of the pyrimidine residue.OaI. G. Leder, Comm. 5th Int. Cong. Biochem. Moscow, 1961, p. 115.lo T. W. Goodwin, “ Recent Advances in Biochemistry,” 3rd ed., Churchill,l1 M. J. Pine and R. Guthrie, J. Bact., 2959, 78, 545.London, 1960392 BIOLOGICAL CHEMISTRYpyrimidines, it was concluded that it was present in the 2-methyl and/orthe 5-hydroxymethyl carbon atoms and incorporated by means of a con-ventional one-carbon transfer ; this view is supported by the observationthat the incorporation is inhibited by methopterin which specifically in-hibits one-carbon transfer. Somewhat similar results have been observedwith the incorporation of [14C]formate into thiamine in baker's yeast.12, 13According to David and Estrarnareix l3 the label is not incorporated intoposition 5 of the pyrimidine residue.Nutritional experiments indicated that isolated pea roots do not haveeven limited synthetic ability with regard to the synthesis of the pyrimidineresidue; the absence of a one-carbon substituent from C(5) or an amino-group from c(6) completely eliminated the growth-promoting activity ofthe residue.14It has already been indicated that 4-amino-5-aminomethyl-2-methyl-pyrimidine is converted into 4 -amino- 5- hydroxy-2 - met hylpyrimidine beforeincorporation into thiamine, and the same is true for 4-amino-5-methoxy-2-methylpyrimidine ;6 presumably the same reaction takes place with the5-aminomethylpyrimidine in the yeast Rhodotorula rubra l5 and in a* thiamine-less strain of the bacterium Escherichia coli which can utilizea combination of the pyrimidine and thiazole residues of thiamine.16 The5-formyl derivative of component (3) was also active in the E .coli strain,16whilst the 5-cyano-derivative was inactive in both A. rubra l5 and E. c0li.1~Very little is known concerning themechanism of formation of the thiazole ring of thiamine. The claim l4 thatisolated pea roots will condense thioformamide with 5-hydroxypentan-2-oneaccording to reaction (6) has not been confirmed in micro- organism^.^Formation of the thiamle residue.O=C-MeI 4 y>TH 2 .CH 2- 0 H/"z\ S+H2C- CH2.CHz.OH HC(6)Harington and Moggridge l 7 postulated that thiazole arose from a-amino-~-(4-methylthiazol-5-yl)propionic acid ( 7 ) which in turn could be formedfrom methionine by the addition of acetaldehyde and an amino-group[reaction ( 7 ) ] . Some support for this view is that ( 7 ) is converted into thethiazole residue by yeast 1 7 and by isolated pea roots.ls Reaction (7) would"NH2' 4- OHCmMe+ H,C CH2*CH2*CH(NH2)*C02H I_f [>:;z- CH(NH2).C02H\S' (7) . . . . . ( 7 ).49, 411.l a D . J. Howells and T. W. Goodwin, unpublished observations, 1961.l3 S. David and B. Estramareix, Biochim. Biophys. Acta, 1960, 42, 562; 1961,l4 J.Bonner and H. Bonner, Vitamins and Hormones, 1948, 6, 225.lsH. Nakayama, Vitamins (Kyoto), 1956, 10, 356, 417; 1957, 11, 20, 169.17C. R. Harington and R. C. G. Moggridge, Biochem. J . , 1940, 34, 685.W. H. Schopfer, Protoplasma, 1938, 31, 105.J. Bonner and E. R. Buchman, Proc. Nat. Acad. Sci. U.S.A., 1938, 24, 431;W. J. Robbins, Plant Physiol., 1940, 15, 547GOODWIN : BIOSYNTHESIS O F THIAMINE 393require that the 4-methyl group should not arise from a one-carbon transfer ;this conclusion is supported by the observation indicated above, that[ 14C]formate is insignificantly incorporated into the thiazole residue ofthiamine by B. subtilis l1 and yeast.12, l3 The variations in the thiazoleresidue which can be tolerated by isolated pea roots are not great.Com-pounds with the following substituents in place of CH,*CH,*OH a t C(5) areactive : CH,CHMe*OH, CH,*CH,*CH,*OH, and, as already indicated,CH,*CH(NH,)*CO,H ; replacement of CH,*CH,*OH by CHMeOOH, or C0,Hresults in an inactive m01ecule.~~ On the other hand, Nakayama l6 reportedthat thiamine-requiring mutants of E . coli (26-43) and Neurospora crassa(185588) which can utilize the thiazole residue of thiamine also respond toa limited extent to 4-methylthiazole. Furthermore, both mutants can bemaintained in the absence of the thiazole residue by either cysteine orthiazolidine-4-carboxylic acid (S), but not by homocysteine, methionine, ormethanol. Because considerable amounts of thiamine and the thiazoleresidue of thiamine accumulated in cultures of these organisms incubatedwith either cysteine or thiazolidine-4-carboxylic acid, reaction (8) was sug-gested as the route for biosynthesis.However, this scheme involves4-methylthiazole as a key intermediate; this is not a very effective inter-mediate in these mutants and, as indicated above, it is completely ineffectivein isolated pea roots. Furthermore, 4-methylC 2-14C]thiazole is not incor-porated into thiamine in a number of micro-organisms.5Plaut l9 has recently suggested a third possible route for the synthesisof the thiazole residue of thiamine. It will be recalled 10 that the thiazolidineI - N -CH*COzH + --+- I l lC02H H2N. CH.CO2H QCIHLN. CH- CH2 CHMe2 HIN-HC -CH CMe2\ / s ..... (9)SHring of penicillin arises from condensation of cysteine and valine [reac-tion (9)]; analogously, cysteine could condense with, e.g., glutamic acid toform a thiazolidine precursor of the thiazole residue of thiamine [reac-tion (lo)].l9 G.W. E. Plaut, Ann. Rev. Biochern., 1961, 30, 409394 BIOLOGICAL CHEMISTRYThiamine Pyrophosphate (TPP, co-carboxylase).-In the late 1930'sacetone-dried powders of brewer's yeast were obtained which could convertthiamine into TPP in the presence of ATP [reaction (11)].20 Since then thisThiamine + ATP + TPP + AMP (11)observation has been frequently repeated with intact and plasmolysed cellsand with the purified enzyme, ATP-thiamine transphosphorylase or thiaminekinase. 21 The reaction mechanism (1 1) has been demonstrated withJ-~~P-ATP; the labelling in the enzymically-formed TPP is consistent withthe direct transfer of a pyrophosphate group.22 Thiamine monophosphateis not a substrate for the purified yeast ATP-thiamine transphosphoryl-a ~ e , ~ , 23 which is activated by Mn2+ up to a concentration of 2 x 1 0 - 3 ~ ,whereafter it becomes inhibitory.23 Traces of inorganic orthophosphate alsostimulate the reaction, whilst molar concentrations are completely inhibi-tory ; the enzyme exhibits a broad pH optimum stretching between 6 and 9. 23A purified preparation free from adenylate kinase, adenine triphosphatase,nucleoside diphosphokinase, and thiamine pyrophosphatase will use thenucleoside triphosphate of uracil, cytosine, hypoxanthine, or guanine inplace of ATP as pyrophosphate donor.24 ATP-thiamine transphosphorylasefrom yeast is inhibited by the pyrimidine residue (3) of thiamine 21 and byoxythiamine (9) 25 but not by pyrithiamine With one possibleMe C + OHAexception, all micro-organisms which require thiamine must possess ATP-thiamine transphosphorylase because their requirements can be satisfied bythe free vitamin. Neisseria gonowham, however, requires TPP for growth,thiamine itself being ineffe~tive.~'ATP-thiamine transphosphorylase from animals is particularly activein red blood cells,2* but has been purified to the greatest extent from liver,where it exists in the mitochondria.28 The mechanism of the reaction isthe same as that observed with the yeast enzyme and its optimum pH is6.8-6-9.2g Similar enzyme preparations have been obtained from ratintestinal mucosa.26, 3O In contrast to the observations made on the yeastS O H .von Euler and R. Vestrin, Natuwiss., 1937, 25, 416; H. Weil-Maherbe,Bwchem. J., 1939, 33, 1997.21 M. A. Lipton and C. A. Elvehjem, Nature, 1940,145,226; H. G. K. Westenbrink,E. P. Steyn-Pawe, and H. Veldman, Biochim. Biophys. Acta, 1947, 1, 154; K. H.Kiessling, Arkiv Kemi, 1956, 10, 279; N. Shimazons, Y. Meno, R. Tanaka, and Y.Kaziro, J . Biochem. (Japan), 1959, 46, 959; T. Mano, ibid., 1960, 47, 283.22 0. Forsander, SOC. Sci. Pennica, Commentationes Phys.-Math., 1956, 19, No. 22.23 E. P. Steyn-Pard, Biochim. Biophys. Acta, 1952, 8, 310.t r y . Kaziro and N. Shimazono, J . Biochem. (Japan), 1959, 46, 963.25A. J. Eusebi and L. R. Cerecedo, Fed. PTOC., 1950, 9, 169.2 6 s . Eich and L. R. Cerecedo, J . BioE. Chem., 1954, 207, 296.27 C. E. Lanford and P. K. Skeggs, Arch. Biochem., 1946, 9, 265.28 H. G. Westenbrink, Proc. XIth Symp. 4th Internat. Cong. Biochem., 1958, p. 73.z o F . Leuthart and H. Nielson, Helv. Chim. Acta, 1952, 35, 1196.80 L. R. Cerecedo, S. Eich, and E. Bresnick, Biochim. Biophys. Acta, 1954, 15, 144GOODWIN : BIOSYNTHESIS O F THIAMINE 395enzyme, it was found that pyrithiamine, but not oxythiamine, inhibits theliver enzyme ;26 indeed pyrithiamine is converted into its pyrophosphate(Koedam, quoted by Westenbrink 28).Rat-kidney particles do not phosphorylate thiamine, but slow incorpora-tion of 32Pi into TPP does O C C U T . ~ ~ On the other hand, S2Pi is quickly incor-porated into TPP by liver mitochondria, but added TPP incorporates thelabel only very slightly.32Thiamine Triphosphate.-This compound, which is present in liver 33 andbaker's yeast,3.l has yet to have a biological function ascribed to it. It isformed by the transfer of an orthophosphate group from ATP to TPPTPP + ATP + Thiamine triphosphate + ADP (12)[reaction (12)], as indicated by experiments with y-32P-ATP.35Hydroxyethylthbmbe Pyroph0sphate.-T hiamine p yrophosphat e is thecoenzyme of yeast carboxylase which decarboxylates a-keto-acids with theformation of the corresponding aldehydes or their condensation products(a-keto-alcohols). Under mildly alkaline conditions the reaction betweenTPP and a-oxo-acids proceeds in the absence of enzyme~,~6 and the dis-covery that, in experiments with model thiazole compounds, the deuteriumof deuterium oxide was rapidly exchanged with the hydrogen of of thethiazole led to the formulation of a mechanism of thiamine participa-tion which involved the formation of a carbanion at of the thiazole ring;this ion would then react with carbonyl-carbonium ions to form hydroxy-alkyl derivatives, which on decarboxylation would yield aldehyde adductsof thiamine.38 The compound which would be derived from pyruvatewould be 3-(4-amino-2-methylpyrimidin-5-yl)methyl-Z-( 1 -hydroxyethyl)-5-( 2-hydroxyethyl)-4-methylthiazole (1 1) ; this has been synthesized andshown to be active, after enzymic pyrophosphorylation, in the carboxylasereaction.39 Carlson and Brown 4O have recently shown that 60-75y0 and25% of the total thiamine present in E . coli and baker's yeast, respectively,is 1-hydroxyethylthiamine pyrophosphate ; it is formed enzymically fromthiamine pyrophosphate and pyruvate in the presence of purified yeast31W. Bartley, Biochem. J., 1954, 56, 379.3aK. H. Kiessling, Acta Chem. Scand., 1957, 11, 97.33 A. Rossi-Fanelli, N. Siliprandi, and P. Fasella, Science, 1952, 116, 711.34K. H. Kiessling, Nature, 1953, 172, 1187.35 K. H. Kiessling, Acta Chem. Scand., 1959, 13, 1358.36S. Mizuhara and P . Handler, J . Amer. Chem. SOC., 1954, 76, 571; E. Yatco-Manzo, F. Roddy, It. G. Yount, and D. E. Metzler, J . Biol. Chem., 1959, 234, 733.37R. Breslow, J . Amer. Chem. SOC., 1957, 79, 1762.38R. Breslow, J . Amer. Chem. SOC., 1958, 80, 3719.39 L. 0. Krampitz, G. Greull, C. S. Miller, J. B. Bicking, H. R. Skeggs, and J. M.40 G. L. Carlson and G. M. Brown, J . Biol. Chem., 1960, 235, PC3; 1961,236,2099.Sprague, J . Amer. Chem. SOC., 1958, 80, 5893396 BIOLOGICAL CHEMISTRYcarboxylase ;40, *l if or-oxobutyrate replaces pyruvate a different compound,probably 1-hydroxypropylthiamine pyrophosphate, is f~rmed.~OIt is very probable that 1 -hydroxyethylthiamine pyrophosphate is“ active acetaldehyde,” the intermediate formed by enzymic decarboxyla-tion of pyruvate, which serves as an aldehyde donor in other enzymicreactions. For example, both wheat-germ 4O and yeast 42 carboxylasesutilize it for the formation of acetoin.T. W. G.T. W. GOODWINE. I. MERCERT. A. SCOTTF. S. STEVENG. R. TRISTRAM41 H. Holzer and K. Beaucamp, Angew. Chem., 1959, 71, 776; H. HoIzer, H. W.Goedder, K. H. Goggel, and B. Ulrich, Biochem. Biophys. Res. Comm., 1960, 3, 599.42H. Holzer and K. Beaucamp, Biochim. Biophys. Acta, 1961, 46, 225

ISSN:0365-6217    

DOI:10.1039/AR9615800353

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

ANALYTICAL CHEMISTRY1. IntroductionIN many branches of analytical chemistry, apparatus originally designedat great cost for investigating fundamental problems of structure and con-stitution is being applied, sometimes at even greater cost, to more particularuses in qualitative and quantitative analysis. At the same time, to meetthe requirements of various technologies, the scope of analysis is beingwidened to include aspects of structure and of physical form which wereonce the reserve of the physicist.In accepting these changes, the analytical chemist must also accept thathis interpretation of the literature of analysis (which is nowadays to befound under many guises), and of such a reflection of the literature as thisReport, must be made with caution. Some of the methods which seemto provide a universal answer in an analytical field can prove cumbersomewhen applied to the complexities of an actual problem.News of rapidadvance in such methods does not necessarily imply progress towards com-mon adoption; it may only betoken activity in ironing out the snags, dis-covering the limitations, and applying the methods in a succession of differingcontexts. Conversely, little progress in a method may be by no meanssynonymous with obsolescence; it could signify a wide acceptance of estab-lished advantages, perhaps of cheapness and directness-daily there muststill be a great many satisfactory analyses carried out gravimetrically bythose denied the pride of possessing an electrifying instrument.AnalyticulAbstracts for 1961 contains abstracts of over 5000 papers.About aseventh of this number is mentioned in the present Report, and the aimof the Reporters has been to select in such a way as to indicate and illus-trate trends in the various sections. In this they have been helped byAnalytical Abstracts, by Current Chemical Papers, and by such authoritativeand critical reviews as those published from time to time in The Analystand in Analytical Chemistry. They have sought to direct the reader’s atten-tion to such reviews, to papers of fundamental worth, and to new methodsand rea.gents, and then to particular applications which illustrate scope ordevelopment.The topics omitted from last year’s Report,2 vix., instrumental methodsof end-point determination in titrimetry, and electrical methods in general,cover two years’ publications, and are inserted appropriately into theprevious pattern and order. The arrangement of the Report is: (1) Intro-duction.(2) General. (3) Basic Operations and Apparatus. (4) Quali-tative Analysis. (5) Methods of Separation. (6) Gravimetric and Titri-metric Analysis. (7) Instrumental End-point Determinations. (8) Deter-mination of Elements in Organic Compounds. (9) Spectroscopic Analysis.(10) Electrical Methods. (1 1) Thermal Methods.At any rate, there is no lack of progress in analysis as a whole.Analytical Abstracts, the Society for Analytical Chemistry, 1961, 8.a Ann. Reports, 1960, 57, 410398 ANALYTICAL CHEMISTRY2. GeneralIn his retiring address as President of the Society for Analytical Chem-istry, R.C. Chirnside gives a thoughtful appraisal of the processes ofdevelopment of analysis, from simple assessment of the commercial valueof a material or check on its conformity with specification, through its exten-sion with the help of the physicist to properties and quality as well as com-position, to the present diversity of disciplines needed to deal with industrialand academic problems and progress. Without minimising the value ofinformation still provided by classical methods, he develops and discussesa new and much wider concept of analysis. In a study of analytical chem-istry in Great Britain,* Chirnside also considers the place of instrumentaltechniques in modern analysis, and the broad requirements of industrialanalytical organisation and methods of analytical teaching, as well as ofthe individual analyst.H. H. Willard, reviewing sixty years of analyticalchemistry,5 emphasises the great changes in the training for and practice ofanalysis, particularly due to advances in instrumental methods during thelast twenty years.The biennial reviews in Analytical Chemistry are this year 6 concernedwith applications of analysis to air pollution, clinical chemistry, coat-ings, essential oils, fertilisers, food, solid and gaseous fuels, ferrous metal-lurgy, non-ferrous metallurgy, pesticides, petroleum, pharmaceuticals,natural and synthetic rubbers, and water. Witlh a total of nearly 5000references, the reviews are an important collection of information in thesefields.Types of paper and other media available for filtration, paper andcolumn chromatography, electrophoresis, spot reactions, the ring oven andion exchange have been described.' The analytical chemistry of berylliumhas been comprehensively reviewed,8 and a bibliography of references tothe analytical chemistry of thorium has been ~ompiled.~ The BritishStandards Institution has published methods for sampling and analysingtin and tin alloys 10 and copper alloys.ll The performance of cupferronanalogues and derivatives has been critically assessed l2 with the conclusionthat, of the many suggested reagents, only a few are satisfactory althoughsome may repay further investigation.Some modern methods, particularly thin-layer and vapour-phase chroma-tography, have been applied to analysis of petrol, oil, tar, and wax in scien-tific criminology.13 A review has been made of the determination of residual3R.C. Chirnside, Analyst, 1961, 86, 314.R. C. Chirnside, Analyt. Chem., 1961, 33, (12), 25-4.H. H. Willard, Talanta, 1961, 7, 152.Analyt. Chem., 1961, 33, No. 5.A. Griine, Osterr. Chem.-Ztg., 1961, 62, 74.M. R. Verma, Jitendra Rai, and Prabhu Dayal, J . Sci. Ind. Res., India, A , 1961,8L. E. Smythe and R. N. Whittem, Analyst, 1961, 86, 83.loBritish Standards Institution, B.S. 3338: Parts 1, 2, 4-8, 11, 12: 1961.l1 British Standards Institution, B.S. 1748: Parts 1-5: 1961.laA. M. G. Macdonald, Ind. Chemist, 1961, 37, 30.13G. Machata, Arch.Kriminol., 1961, 127, 1.Suppl. to 20 (2) and 20 (3)CARTWRIGHT, WESTWOOD, AND WILSON 399organo-phosphorus insecticides in foodstuffs 1 4 and a method is recommendedfor determining mercury residues in apples and t0mat0es.l~A comprehensive and critical review has been made of methods of deter-mining nucleic acids in biological materials.16 In the field of water pollu-tion there has been a review of the literature of 1960, including a surveyof analytical methods,l7 and a comparison of methods for determiningchlorine. 1*The Harvard method of determining atomic weights, involving titrationof halides with silver nitrate, has been critically reviewed by A. F. Scott,lgwho points out conditions under which the nephelometric end-point mayhave involved small errors.Difficulties in applying and assessing the value and limitations of statisti-cal methods have been appreciated by Pantony 20 in a chemist’s introduc-tion to statistics, theory of error, and design of experiment.Lewin hasdiscussed variations and errors in experimental investigations 2 1 under theheadings of general causes, compromise errors, insufficient formulations andinaccurate assumptions, limitations of chemical tools and techniques, andpersonal and characteristic errors. Following a symposium on the qualityof observations, papers have been published 22 on the meaning and evalua-tion of precision and accuracy, and the analysis of planned experiments.To facilitate comparisons of performance of analytical methods, definitionsof precision and limit of detection on a uniform basis have been discussed 23with emphasis on the need for including information on behaviour of blankdeterminations.Problems of blanks in the determination of trace elementshave been reviewed,24 and complications in determining errors and con-fidence limits of indirect analyses, due to difficulties in calculating thenumber of degrees of freedom, are discussed by Gorli~h.2~ A further pleais made by Veibel 26 to express analytical results in terms of ‘‘ molecularindices ” instead of, for example, “ acetyl value,” whereby a clearer deduc-tion of structural forniulz may be made.3. Basic operations and apparatusThe operations and apparatus described here are those common to aExcept for some notorious materials, and in very precise work, errorsvariety of analytical methods.l4 E.D. Chilwell and G. S. Hartley, Analyst, 1961, 86, 148.l5 Joint Mercury Residues Panel, Analyst, 1961, 86, 608.l6 W. C. Hutchison and H. N. Munro, Analyst, 1961, 86, 768.l i Research Committee, Water Pollution Control Federation, J . Water Pollut.leM. C. Rand and J. V. Hunter, J . Water Pollut. Control Fed., 1961, 33, 393.19A. F. Scott, Analyt. Chem., 1961, 33 (9), 2 3 ~ .2o D. A. Pantony, The Royal Institute of Chemistry, Lecture Series 1961, No. 2;J . Roy. Inst. Chem., 1961, 85, 411.21 S. Lewin, Lab. Practice, 1961, 10, 99, 162, 363, 474, 556.22 R. B. Murphy, Muter. Res. and Stand., 1961, 1, 264; W. J. Youden, ibi&., p. 268;W. S. Connor, ibid., p. 272; M.E. Terry, ibid., p. 273.23A. L. Wilson, Analyst, 1961, 86, 72, 272.2 r M . Kniiek and J. Provaznik, Chem. Listy, 1961, 55, 389.25P. Gorlich, 2. analyt. Chem., 1961, 179, 266.4 6 S. Veibel, Chim. analyt., 1961, 43, 189.Control Fed., 1961, 33, 445400 ANALYTICAL CHEMISTRYin weighing due to accumulation of electrostatic charges are not commonin British climates. In many countries, and in artificially dry atmospheres,however, they can be serious. By weighing the material inside a thin-walled metal tube, these errors have been overcome in the case of a chargedpolyethylene rod weighed on a microchemical balance ;27 this may havewider application. A statistical appraisal of various contributions to theover-all precision of pipette usage, and an investigation into the effects ofvarying the technique of delivery, have been made by Dean and Herring-shaw.28 Results obtained in a series of controlled experiments are in verygood agreement with the effects calculated, and show that with carefultechnique the largest error is in setting the meniscus to the mark.The studyof variables has enabled a recommended procedure to be made for obtainingthe highest precision under ordinary conditions of use.Small liquid samples may be dried speedily and without bumping byplacing them beside the desiccant in a closed vessel fitted with a paddle toagitate the air;29 contamination of one volatile sample by another mustbe avoided.An improvement is described 30 in the electrolytic hygrometer of Keidel 31for measuring traces of water in gases; the absorbing surface is an externalone and is readily removed for cleaning.The preparation of standard mix-tures of gases for calibration purposes is facilitated by a simple apparatuscomposed of calibrated glass syringes and a football bladder. An easilyconstructed lock has been described for introducing solid samples into ahigh-vacuum system. 33A method for constructing multi- junction thermopiles from fine wireenables piles of over 80 junctions to be readily assembled.34 An automaticmelting point recorder, dependent on the movement of a thermocouplepiston supported by the unmelted solid, gives quick results and does notrequire critical control of heating rates.a5 The boiling point of a drop ofliquid may be obtained by an improved Siwoloboff method,36 agreementwithin 1" of the literature value being obtained for a large number ofsamples.A new indicator, benzaldehyde p-nitrophenylhydrazone, has beendescribed 37 for the pH range 11-12, having the yellow hydrazone formbelow pH 11.3 and the red anionic form above pH 11-7.A pH standardfor blood and other fluids in the range 7-8 has been obtained from solutionsof potassium and sodium hydrogen phosphates;38 its values are listed from0" to 50'. By fitting an adapter unit to a pH meter, its sensitivity can be27 Tetsuo Mitsui and Keikichi Yoshikawa, Mikrochim. Acta, 1961, 527.28 G. A. Dean and J. F. Herringshaw, Analyst, 1961, 86, 434, 440.29H. G. Wager, Analyst, 1961, 86, 266.30E. Barendrecht, Analyt.Chim. Acta, 1961, 25, 402.31 F. A. Keidel, Analyt. Chem., 1959, 31, 2043.32 J. Lacy and K. G. Woolmington, Analyst, 1961, 86, 547.33A. Parker, Analyst, 1961, 86, 550.34 C. A. Glover and R. R. Stanley, Analyt. Chem., 1961, 33, 477.35 L. F. Berhenke, Analyt. Chem., 1961, 33, 65.36 C. Karr, jun., and E. E. Childers, Analyt. Chem., 1961, 33, 655.37 R. O'Connor, W. Rosenbrook, jun., and G. Anderson, Analyt. Chem., 1961, 33,3eV. E. Bower, M. Paabo, and R. G. Bates, Clin. Chena., 1961, 7, 292.1282CARTWRIGHT, WESTWOOD, AND WILSON 401increased to give one pH unit for full-scale deflection on an auxiliary meter 39without detectable drift during a titration.The general equipment and techniques used in ultramicrochemicalmanipulations have been discussed, and potentiometric and amperometrictitrations 40, *1 and chromatographic separations and electrolytic deter-minations 41 have been carried out on this scale.-4. Qualitative analysisInorganic.-Interference in systematic cation analysis by the thio-sulphate ion, which on acidification causes precipitation of sulphides andsulphates as well as sulphur, is resolved by a scheme by W.F. Jones 42 whoselectively extracts from the precipitate first lead, then copper and arsenic,followed by silver and mercury, with provision for detecting insolublesulphates. Thioformanilide has been claimed 43 to be better than thioacet-amide for precipitating sulphides in qualitative analysis, in giving morecomplete precipitation of cadmium, tin(Iv), and lead.A scheme for system-atic identification of calcium, strontium, and barium 44 involves solutionof the perchlorates in acetone, precipitation of barium with nitric acid,followed by chromate, and separation of calcium from strontium by extrac-tion with butanone-nitric acid-acetic acid-acetic anhydride. The co-precipitation of cobalt with aluminium-group hydroxides in qualitativeanalysis has been examined by using cobalt-60 tracer, and was found tobe most serious with chromium ; in semimicro-analysis, precipitation of thehydroxides by the homogeneous method using urea is advocated.45Among procedures for the detection of a number of different ions,Stewart 46 uses a solution of myristic acid in light petroleum applied to thesurface of a dilute solution in a shallow trough. The reagent forms a uni-molecular film which acts as a cation collector, and by compressing the filmwith a barrier the cations may be transferred to a filter-paper strip for detec-tion by suitable reagents.Sensitive and selective colour reactions are used 47to detect calcium, copper, zinc, cobalt, nickel, and palladium (alone amongthe platinum metals) by reaction with a number of azoxy-derivatives ofpolydentate chelating agents. The colour reactions of metals and offluoride with nitrosochromotropic acid have been investigatedY48 and testsare described for copper, cobalt, nickel, and palladium; fluoride is detectedindirectly. A number of bivalent cations which form complexes with 2-hydroxynaphthaldehyde can be identified in low concentration by thecrystal forms obtained.49Among the many methods published for det,ection of individual cations39H.Jackson, Analyst, 1961, 86, 76.4 0 W. Helbig, Z . analyt. Chem., 1961, 182, 15.41 I. P. Alimarin and M. N. Petrikova, Talanta, 1961, 8, 333.42W. F. Jones, Milcrochim. Acta, 1961, 214.43M. B. Antia, R. C. Arora, and R. P. Bhatnagar, Analyst, 1961, 86, 202.44P. Luis, Mikrochim. Acta, 1961, 529.45P. H. Bailey and R. W. C. Broadbank, Analyst, 1961, 86, 485.4sF. H. C. Stewart, Chem. and Id., 1961, 1064.47V. M. Dziomko and K. A. Dunaevskaya, Zhur. analit. Khim., 1960, 15, 661.‘ t ~ Sachindra Kumar Datta and Sachindra Nath Saha, iMikrochim. Acta, 1961, 361.4e S. I. Gusev, V. I. Kumov, and Z. A.Bitovt, Zhur. analit. Khim., 1960, 15, 746402 ANALYTICAL CHEMISTRYand anions is the detection of boron in silicate ores by grinding them withquinalizarin and then adding a drop of sulphuric acid;50 for larger quantitiesof boron a blue colour develops in the cold, and for smaller quantities onheating. Highly coqdensed phosphates can be detected and separated 51with no reaction from mono-, di-, and tri-phosphates and trimetaphosphates,or from silicates, by precipitation with cinchonine sulphate. Chromate maybe detected in dry material in the presence of dichromate and vice versa.52A method for detection and semiquantitative determination of uranium 53 isbased on the intense fluorescence in ultraviolet light of uranyl ion adsorbedon a silica-gel column.A stable red complex of cobalt, claimed 54 to bespecific, is formed with the p-nitrophenylhydrazone of 3-isonitrosopentan-2-one. Other reagents investigated for detection of cobalt are the p-nitro-phenylhydrazone of pyruvaldoxime 55 and, for very small quantities, thetiron-orcinol-hydrogen peroxide and other systems 56 which are stronglycatalysed by cobalt ions; trace amounts of osmium can similarly be detectedby catalysis of oxidations by hydrogen peroxide and by potassium chlorate.57Ruthenium(m) reacts with p-phenylenediamine, but not with the ortho- andmetcc-isomers, to give a violet colour which turns brownish-black;58 this canbe used as a test for either the metal or the reagent.Organic.-The detection of elements in organic compounds has beendiscussed.59 A new and very sensitive test for nitrogen,60 which gives posi-tive results below the level of the Lassaigne test, depends on conversion ofthe cyanide produced by sodium fusion, first into cyanogen chloride withchloraniine T, and then, by reaction with dimedone in pyridine, into poly-methine dyes.Of the very large number of published tests for the identification ofgroups of compounds and individual compounds, only a selection of themore generally useful or interesting ones can be included.Spot tests aregiven for a number of unrelated compounds 61 and for others using detectionin the gaseous phase of products formed by reaction with Devarda's alloyand Raney nickel. 62 Begemann discussed the identification of alcohols,sulphides, and carbonyl compounds e3 present in complex mixtures by forma-tion of derivatives and separation by paper chromatography.Three tests are given for detecting and distinguishing organic peroxides.64Detection of small quantities of p-cresol by coupling with diazotised p-nitro-50 E. P. Ozhigov, V. S. Lozinskaya, and A. L. Krasnitskaya, Zhur. analit. Khim.,1961, 16, 315.51 C. Riess, 2. analyt. Chenz., 1961, 179, 358.52W. F. Jones, Mikrochim. Acta, 1961, 88.53Z. sulcek, J. Michal, and J. Doleial, Chemist-Analyst, 1961, 50, 13.54V. D. Anand, Mikrochim. Acta, 1961, 650.55V. D. Anand, Chemist-Analyst, 1961, 50, 44.56 J. Bogn6.r and 0. Jellinek, Magyar Kim. Folydimt, 1961, 67, 100, 103.57 J. BognAr and S. S&rosi, Magyar Kkm. Folydirat, 1961, 67, 193, 198.'j8Anil K.Mukherji, Mikrochim. Acta, 1961, 1.59 W. I. Stephen, Ind. Chemist, 1961, 37, 86; Chem. Weekblad, 1961, 57, 273.6oA. Sp6v&k, V. Kratochvil, and M. VeEeFa, Coll. Czech. Chem. Cmm., 1961, 26,61 F. Feigl, D. Goldstein, and D. Haguenauer-Castro, 2. analyt. Chem., 1961,178,419.62 F. Feigl, AnaZyt. Chem., 1961, 33, 1118.63P. H. Begemann, Chem. Weekblad, 1961, 57, 293.64 G. H. Foxley, Analyst, 1961, 86, 348.887CARTWRIGHT, WESTWOOD, AND WILSON 403aniline and treatment with magnesium oxide, giving a blue colour, is notinterfered with by the other isomers or by phen01,6~ but resorcinol and someother compounds behave similarly. Tests are described for the detectionof resorcinol, quinol, and catechol, each in presence of a large excess of theothers ;66 neither the trihydroxybenzenes nor di- and tri-aminobenzeneinterfere. A number of copper-substituted pyridines have been comparedas reagents for organic acids 6 7 by spot tests, extractive tests, or micro-scopic examination of crystalline products.For the characterisation ofaldehydes in the presence of ketones, (-J-)- 1,2-dianilino-l,2-diphenylethanegives derivatives with sharp melting points.68 Ketoses may be distinguishedfrom aldoses by the ultraviolet fluorescence shown when their spots, sepa-rated by chromatography, are treated with sulphosalicylic acid. Chroma-tographed spots of glycerides may be distinguished by periodateSchWsbase reagent, with which diglycerides react at once, while monoglyceridesrequire prior decomposition with, e.g., hydro~ylamine.7~ A spot test form-nitroaniline, using phenylhydrazine hydrochloride, is claimed to bespecific.71 Spot-test detection and colorimetric determination of about100 aromatic amines and imino hetero-aromatic compounds 72 uses S-methyl-2-benzothiazolinone hydrazone as reagent. Detection is possible of each ofthe phenylenediamine isomers in presence of the 0thers,~8 and piperidinecan be detected by a spot test in the presence of piperazine and vice v e r s c ~ . ~ ~Reactions of tetraphenylborate ions can serve as a method of preparing use-ful derivatives of some hydroxyarylamines and hydroxyhetero( N ) hydro-c a r b o n ~ , ~ ~ as well as in detecting the reagent. Chloropicrin can be detected,the method being applicable to air samples, by reaction with bromide-cyanide, pyridine, and aniline hydrochloride, applied successively or inadmixture.76A number of spot tests have been described for arylsulphinic acids.77A criticism of methods for the identification of surface-active agents in food-stuffs 78 has been criticised in turn.795. Methods of separationSolvent Extraction.-Separation of metals by selective extraction of theircompounds, or more usually their complexes, into organic solvents continues65 F. Feigl and V. Anger, Analyt. Chem., 1961, 33, 89.66T. S. Ma and A. Hirsch, Chemist-Analyst, 1961, 50, 12.67A. Sa and D. B. Budzko, Rev. ASOC. bioquim. argentina, 1960, 25, 103.6 8 R . Jaunin and J.-P. Godat, Helv. Chim. Acta, 1961, 44, 95.68 E.S. Rorem, Analyt. Biochem., 1960, 1, 218.70B. F . C. Clark, J . Chromatog., 1961, 5, 368.71 F. Feigl and V. Anger, 2. analyt. Chem., 1961, 182, 13.72 E. Sawicki, T. W. Stanley, T. R. Hauser, W. Elbert, and J. L. Noe, Analyt. Chem.,73 A. Hirsch, S. Fishman, M. Goldberg, M. Ottensoser, and M. Schachnow, Chemist-74F. Feigl, Chemist-Analyst, 1961, 50, 15, 18.76R. Neu, Mikrochim. Acta, 1961, 32.78H. Drtecke and R. Kraul, 2. analyt. Chem., 1961, 178, 412.7 7 F . Feigl, D. Haguenauer-Castro, and E. Libergott, Mikrochim. Acta, 1961, 595.78 W. Ciusa, and G. Brtrbiroli, Boll. Lab. Chim. Provinciali, 1961, 12, 30.79 F. Muntoni, Boll. Lab. Chirn. Provir?.ciaEi, 1961, 12, 215.1961, 33, 722.Analyst, 1961, 50, 7 404 ANALYTICAL CHEMISTRYto attract many workers.Earlier papers set a high standard in thorough-ness of investigation, and this has generally been maintained. The workreported here has been selected from a wide field to demonstrate develop-ments in the scope and potentialities of the method, which finds its mostuseful application in the separation of small quantities of a particular ele-ment, which can then often be determined directly by spectrophotometry.of the extraction of 57 metals asquaternary amine (propyl, butyl, and hexyl) complexes into isobutyl methylketone from four acid and one alkaline media. Many separations withanalytical possibilities in both radiochemical and general fields have beentabulated. The behaviour of the acetylacetonates of 18 metals on extrac-tion into chloroform at varying pH has been investigated,81 and correlatedwith the ionic character of the metals. The use of dithizone as an extractantfor metals has been briefly discussed.82 A study has been made of the extrac-tion of copper-64 from aqueous hydrochloric acid solution into a chloroformor carbon tetrachloride solution retained on silica gel, the results suggestingthe possibility of adopting solvent-extraction to work on the column prin-ciple.83The effect of quaternary ammonium salts on the 8-hydroxyquinolineextraction of magnesium has been studied a4 and a method is proposed whichseparates magnesium from calcium, strontium, and barium. Further thio-nine derivatives have been studied 85 for the extraction of boron, and satis-factory combinations of extractant and solvent have been discovered.Small amounts of aluminium may be extracted by 8-hydroxyquinoline fromsolution of siliceous materials, after first extracting iron and titanium.86Extraction of iodo-complexes of indium and thallium into ether solution isused as a preliminary to the spectrographic determination of the metals inrocks. 87 A number of solvents and solvent mixtures were investigated forthe separation of phosphate from arsenate ;*8 butanol-chloroform was themost effective, but clean separation was not possible in one extraction. Theextraction of arsenic(1n) from hydrochloric acid solution into a benzenesolution of catechol has been re-exarnined,ag and it was found that aboveSN-acid, catechol has little effect, and effective separation of arsenic fromantimony and bismuth is obtained with benzene alone.Extraction ofiodide using cadmium and a tributyl phosphate-butyl methyl ketonesolvent is an example of anion separation when suitable complexes canbe formed.Yttrium can be quantitatively separated from lanthanum and ceriumA very full study has been made80 W. J. Maeck, G. L. Booman, M. E. Kussy, and J. E. Rein, Analyt. Chem., 1961,81 Tsunenobu Shigematsu and Masayuki Tabushi, Bull. Inst. Chem. Res., Kyoto82 H. Freiser, Chemist-Analyst, 1961, 50, 62.83T. B. Pierce, AnaZyt. Chim. Acta, 1961, 24, 146.8 4 s . J. Jankowski and H. Freiser, AnaZyt. Chem., 1961, 33, 776.S S L . Pasztor and J. D. Bode, Analyt. Chim. Acta, 1961, 24, 467.seF.VlbEil and V. ZBtka, Chem. prumysl, 1961, 11, 139.87R. R. Brooks, Analyt. Chim. Acta, 1961, 24, 456.a8H. H. Ross and R. B. Hahn, Talanta, 1961, 7, 276.89 H. C. Beard and L. A. Lyerly, AnaZyt. Chem., 1961, 33, 1781.OOP. W. West and A. S. Lorica, Analyt. China. Acta, 1961, 25, 28.33, 1775.Univ., 1961, 39, 35CARTWRIGHT, WESTWOOD, AND WILSON 405by extraction from nitric acid solution by tributyl pho~phafe,~~ the methodbeing applicable to the determination of strontium-90 which decays to giveyttrium. The extraction of zirconium into xylene as the Z-thenoyltrifluoro-acetone complex has been improved 92 to reduce variability of recovery.It has been suggested 93 that the extraction of zirconium by tributyl phos-phate owes its effectiveness to the presence of dibutyl phosphate.Tributylphosphate has been used to extract vanadium( v) from hydrochloric acidsolution, and interferences have been studied.94 Effective separation ofiron from vanadium and chromium can be achieved by extracting ferricchloride with isopfopyl ether.95 Technetium and rhenium can be separatedfrom uranium by extraction with pyridine from sodium carbonate solution.96The extraction of uranium complexes with dibenzoylmethane into carbontetrachloride, chloroform, and benzene has been studied 97 and comparedwith results on use of acetylacetone and benzoylacetone. Successive extrac-tion of copper, iron, and cobalt forms the basis of a method for their deter-mination in electrolytic Osmium can be determined in uranylsolutions following oxidation to osmium tetroxide and extraction intochloroform. 99A method which is specific for plutonium depends on the extraction intois0 bu t yl met h y 1 ketone of the t et r aprop y lammonium nit rate-plut onium ( VT )complex from an acid-deficient salting solution.100 A selective method forcopper l01 is based on reduction with ascorbic acid to copper(1) and extrac-tion with triphenyl phosphite in carbon tetrachloride; gold can be extractedinto chloroform from chloride solution with tetraphenylarsonium chloride.l 0 2Solvent extraction can usefully be applied to isotopic dilution analysis, asin the case of zinc.lO3As well as its usual application to the separation of a metal, solventextraction can be employed to determine the extracting agent.An exampleof this is the improvement in the method for determining amines lo4 byextracting the amine-cobalt thiocyanate complex into pentyl alcohol-kerosene mixture.Solvent extraction has also been discussed as a general method forrecovery, purification, and identification of drugs and their metabolic pro-ducts, lo5 with particular reference to barbiturates.91 A. S. Goldin and R. J. Velten, Analyt. Chem., 1961, 33, 149.9zS. F. Marsh, W. J. Maeck, G. L. Booman, and J. E. Rein, Analyt. Chem., 1961,93 R. 3'. Rolf, Analyt. Chem., 1961, 33, 149.9p Santosh K. Majumdar and Anil K. De, Analyt. Chenz., 1961, 33, 297.95 G. A. Dean and J. F. Herringshaw, Analyst, 1961, 86, 106.S. J. Rimshaw and G. F. Malling, Analyt.Clzern., 1961, 33, 751.97 V. MouEka and J. Star9, Coll. Czech. Chem. Cornm., 1961, 26, 763.O 8 S. E. Kreimer, A. V. Stogova, and A. S. Lomekhov, Zavodskaya Lab., 1961, 27,gs G. Goldstein, D. L. Manning, 0. Menis, and J. A. Dean, Talanta, 1961,7,296,301.loo W. J. Maeck, M. E. KUSSY, G. L. Booman, and J. E. Rein, Analyt. Chem.,lolT. H. Handley and J. A. Dean, Analyt. Chem., 1961, 33, 1087.lo2 J. W. Murphy and H. E. Affsprung, Analyt. Chem., 1961, 33, 1658.lo8 J. Starjr and J. RfiiiEka, Talanta, 1961, 8, 296.lMP. J. Lloyd and A. D. Cam, Analyst, 1961, 86, 335.lo5M. T. Bush, Microchern. J., 1961, 5, 73.33, 870.386.1961, 33, 998406 ANALYTICAL CHEMISTRYChromatography.-The term is, as in the last Report, limited to liquid-phase separations on columns, paper, gels, or thin films, and separate con-sideration is given to electrophoresis, ion-exchange and gas chromatography.Except in the field of thin-film chromatography, the bulk of the considerablevolume of published work has concerned either modifications to improveexisting applications, or new applications of established techniques, few ofwhich can be reported.A survey has been given106 of the varioustypes of liquid-liquid and solid-liquid chromatography, with discussion ofvarious methods of detecting the solute.Theoretical condideration has beengiven to the mechanism and efficiency of linear chromatographic processesand has been applied to analytical separations of solutes 107 and discussedin terms of the strength and distribution of adsorption sites, with thermo-dynamic treatment of results obtained with series of organic compoundsusing several solvents.lo* Procedures for activating and standardisingsilica have been published which allow the reproducible selection of any of10 grades of activity.lo9 A novel stationary phase is composed of fragmentsof rubber swollen by toluene, used with toluene as mobile phase;llO tetra-fluoroethylene has been used as column medium for separation of lipids.ll1Devices have been described for automatic fraction sampling for analy-sis,112 for automatic titration of eluted organic acids,113 and for continuousspectrophotometric monitoring of eluates.114, 1 1 5 9 116No report is given of applications to particular separations; they con-tinue to be concerned largely with separations of ionic species by means ofmixed organic solvents, and of a wide variety of organic compounds, in bothcases followed by identification and often determination using colour reac-tions or spectrophotometry.Paper chromatography. A review has been published of methods andapparatus used in quantitative radio paper chromatography.117 In deter-mining carbon-14 in paper chromatograms, it is recommended that the spotsbe scanned from both sides of the paper and the results averaged.ll8 Theinfluence of pH on the RF values of organic acids, by use of neutral solvents,has been investigated;llg the results are interpreted in terms of the effect ofthe substituents on the dissociation constant of the acid group.A method has been devised for .applying solutions rapidly to paper toform a spot via a cotton thread passed through the paper,lZ0 and a thin106 G.Dijkstra, Chem. Weekblad, 1961, 57, 189.107P. C. Haarhoff and V. Pretorius, J . S . African Chem. Inst., 1961, 14, 22.1O8L. R. Snyder, J . Chromatog., 1961, 5, 430; 6, 22.lo9 R. Hernandez, R. Hernandez, Jun., and L. R. Axelrod, Analyt. Chem., 1961, 33,1lOP. I. Brewer, Nature, 1961, 190, 625.111A. C. Arcus and G. G. Dunckley, J . Chromatog., 1961, 5, 272.112 R. J. Rowlands, J . Chromatog., 1961, 6, 58.llaO. Forsander and P. Neuenschwander, J . Chromatog., 1961, 5, 515.l14N. G. Anderson, Analyt. Chem., 1961, 33, 970.115 F. Alderweireldt, J . Chromatog., 1961, 5, 98.116 J. H. Young, Analyst, 1961, 86, 520.l17F.Pocchiari and C. Rossi, J . Chromatog., 1961, 5, 377.ll8H. J. M. Hansen, Acta Chem. Scad., 1961, 15, 670.ll0A. Panek and R. Leibsohn, J . Chromatog., 1961, 5, 308.120D. P. Dearnaley and R. M. Acheson, J . Chromatog., 1961, 5 , 452.Column chroma.tography.370CARTWRIGHT, WESTWOOD, AND WILSON 407reproducible line of solution can be applied by using a hypodermic syringecontrolled mechanically.121 Devices for evaporating solvent during appli-cation of the sample, by means of a stream of nitrogen,122 and for air-dryingstrip chromatograms by using glass Buchner funnels, 123 have been described.Many separations of groups of cations by paper chromatography, fol-lowed generally by spot-test identification, have been carried out.Mer-cury(n), lead, bismuth, copper, and cadmium have been separated by meansof hydrochloric or sulphuric acid media.124 Acetates of iron(m), nickel,cobalt, zinc, silver, cadmium, mercury, lead, and uranium(m) can be sepa-rated by two-dimensional elution with acetone-acetic acid and ethanol-acetic acid.125 Ascending elution with 60% ethanol in presence of varyingamounts of citrate, tartrate, and oxalate serves to separate mixtures of upto 5 of 10 common metals.126Beryllium is separated, and determined by a colour reaction comparedwith standards, by ascending elution with a water-hydrochloric acid-ethylmethyl ketone solvent on paper previously impregnated with EDTA.12'Tin is similarly determined by using butanol-hydrochloric acid-waterseparation on plain paper.l28 Copper and zinc can be isolated separatelyas their 8-hydroxyquinolates with butanol-hydrochloric acid-water oncircular paper, followed by titrimetric determination with EDTA.129Separation of copper, nickel, and cobalt after treatment with excess ofthiocyanate was achieved l30 by using ammonia-pyridine-alcohol solvents.Rapid trace analyses of phosphate mixtures 131 and pyrophosphates andpolyphosphoric esters 132 have been described.In the organic field, paper chromatography continues to be widely usedto isolate small quantities of pure compounds for identification by colourreactions or determination by spectrophotometry.Classes of compoundshave been investigated ; separation and identification of 3,5-dinitrobenzoylderivatives of a large number of alcohols, glycols, polyoxyethylene glycols,phenols, thiols, and amines by using various solvents and papers have beendescribed.133 RF values are given 134 for 50 aldehydes and ketones aftercondensation with cyanoacetic acid hydrazide, by means of chloroform onimpregnated paper.Diglycerides are separated from and detected in thepresence of monoglycerides, 70 and mixed sugars in fermenting liquors areseparated by rapid horizontal paper chromatography a t 60 O for identifica-tion and determinati0n.l3~ In the presence of monobasic acids, which move121S. W. McKibbins, J. F. Harris, and J. F. Saeman, J . Chromatog., 1961, 5, 207.ln2V. H. Booth, J . Chromatog., 1961, 6, 95.lZ3 J. Goldyn, J . Chromatog., 1961, 5, 372.124V. K.Mohan Rao, J . Sci. Ind. Res., India, B, 1961, 20, 109.125H. S. R. Barreto, R. C. R. Barreto, and I. P. Pinto, J . Chromatog., 1961, 5, 5.la6 E. J. Singh and Arun K. Dey, Analyt. Chim. Acta, 1961, 24, 444.12' D. Ader and A. Alon, Analyst, 1961, 86, 125.128 S. Fisel, H. Franchevici, and Gh. Bilan, Rev. Chim. ( h a d . R.P.R.), 1961,6, 175.leST. D. Miles, A. C. Delasanta, and J. C. Barry, Analyt. C h m . , 1961, 33, 685.130M. R. Verma and P. K. Gupta, Current Sci., 1961, 30, 10.lS1 R. H. Kolloff, Analyt. Chem., 1961, 33, 373.132 P. L. Ipata and R. R. Manaresi, Boll. SOC. ital. BioE. sper., 1961, 37, 464.133 J. Gaspmi6 and J . BoreckJi, J . Chromatog., 1961, 5, 466.134 J. Franc and G. Celikovsk8, ColZ. Czech. Chem. Comm., 1961, 26, 667.135 J. B.Himes, L. D. Metcalfe, and H. Ralston, AnaZyt. Chem., 1961, 33, 364408 AN AL Y T I C AL CHEMISTRYwith the solvent front, C6-cl2 dibasic acids can be separated and identi-fied.l36 A review has been published137 of the chromatographic separa-tion, both column and paper, of porphyrins and metallo-porphyrins.Thin-layer chromatography. Chromatography on glass plates spreadwith thin layers of adsorbents such as silica gel, alumina, or kieselguhr,generally mixed with a binding material, has advantages in compactness,rapidity of equilibration and development, sharpness of separation, andscope for application of identifying reagents. Although reproducibility maynot be so high as with paper, applications of the technique have been growingrapidly.A review 138 deals with its development, methods, and typicaluses, and another covers recent progress. 139 Separations of lithium, sodium,potassium, and magnesium, 140 and applications to vitamin identification,l41are examples of its uses in inorganic and organic analysis.Electrophoresis.-High-voltage paper electrophoresis using potentials ofmore than 50 v per cm. and energy input of 1 w per sq. cm., dissipated byaluminium heat-exchangers, has been described 142 for rapid separationswith high resolution of complex mixtures of compounds of low molecularweight. Direct recording of optical density of closely spaced bands obtainedby paper electrophoresis is possible by using an apparatus 143 which passesthe strip, soaked in paraffin oil, a t constant speed across a narrow lightbeam.Suitable treatment of starch gel after electrophoresis and staining cantransform it into a transparent flexible film which can be used for directphotometry.144 Polymerised acrylamide, used as a gel, gives a similarThe behaviour of some acids and salts in altering the pH, often radically,during paper electrophoresis has been studied, and its effects on inorganicseparations have been discussed.146 The addition of phenol has beenfound 147 to improve the separation of potassium, rubidium, and czsium bypaper ionophoresis.Continuous electrophoretic separation of radioactivecadmium and indium has been described.148Paper electrophoresis has been used to separate glycine and permit itsdetermination by ninhydrin in protein hydrolysates, 149 and to separatehzmoglobin A, from blood samples for spectrophotometric determina-tion.150 It has also been used in the separation and characterisation ofa number of local anzsthetics.151fiim.145136 J.L. Occolowitz, J . Chromatog., 1961, 5, 373.137 J. E. Falk, J . Chromatog., 1961, 5, 277.138 E. G. Wollish, M. Schmall, and M. Hawrylyshyn, Analyt. Chem., 1961, 33, 1138.139 E. Demole, J . Chromatog., 1961, 6, 2.14oH. Seiler and W. Rothweiler, Helv. Chim. Acta, 1961, 44, 941.141 E. Nurnberg, Apoth.-Ztg., 1961, 101, 268.142 D. Gross, J . Chromatog., 1961, 5 , 194.143 Anon., Lab. Practice, 1961, 10, 287.144 J. Groulade, J. M. Fine, and C. Ollivier, Nature, 1961, 191, 72.145 S. Raymond and Y.-J. Wang, AnaEyt.Biochem., 1960, 1, 391.146 Z. Szponar, Chem. Analit., 1961, 6, 187.147 T. Pompowski, J. Kowalczyk, and I. Siemianowska, Chem. AnaZit., 1961, 6, 393.l48Z. Konrad-Jakovac and Z. PuEar, Croat. Chem. Acta, 1961, 33, 33.149 J. Saint-Blancard and J. Storck, Ann. pharm. frang., 1960, 18, 711.l5OR. N. Ibbotson and B. A. Crompton, J . Clin. Path., 1961, 14, 164.15lV. Jokl and V, Sukupov&-Kolkov&, Cesk. Farm., 1961, 10, 197CARTWRTCJHT, WESTWOOD, AND WILSON 409Ion Exchange.-Ion-exchange methods continue to be generally used forremoving interfering ions from solution before applying a particular methodof determination, as, for example, in the treatment of mineral solutions forthe flame-photometric determination of copper. 152 Treated resins are alsoused to fix, and then recover, particular ions, as in the separation of lead ona sulphate-treated anion exchanger, followed by elution with sodiumhydroxide solution.153 Attention has been given to the use of paperimpregnated with the ion exchanger ; zirconium phosphate,154, 155 hydratedzirconium oxide, and zirconium tungstate 156 have been used, as well aslong-chain tertiary amines such as tri-n-octylamine.157 Experiments havesuggested 158 that sodium halide mixtures may be separated by placing thesolid halides on a sodium-form resin column and elution with 80% aqueousacetone.Salting-out chromatography, which is the separation of non-electrolyteson ion-exchange resins with salt solutions as eluents, has been reviewed anddiscussed l 5 9 from the point of view of theory and application. A novelseparation method, called ligand exchange, has been described 160 in whichmetal ions such as copper-(I) or -(II), nickel, silver, or cobalt(m) are held ina column of ion-exchange resin.hydric alcohols, olefins, amino- and organic-acid anions are strongly ad-sorbed, since they form strong complexes with the metals.Selective dis-placement of ligands allows sharp separation of very small quantities to beachieved; little resin need be used because of the strength of the complexformation.Gas Chromatography.-When mixtures, simple or complex, of materialswith moderate vapour pressures are to be separated, many techniques whichhave served their day have given way to gas chromatography. This isreflected in the continuing very large number of papers in which the methodis used for identification, for direct determination by ratio of peaks or bycomparison with standards, or as a preliminary to other methods of deter-mination.Chovin has reviewed 161 the derivation and applications of separationfactors, retention indices, and effects of adsorption a t the gas-liquid inter-face.A review of applications of gas chromatography162 contains 349references. Precision and accuracy of the method have been investi-gated 163 by repeated separation of a propane-butane mixture. The choiceof solid supports 164 and of solvents 1e5 has been studied. General rules forLigands such as ammonia, amines, poly- .lS2 W. G. Schrenk, K. Graber, and R. Johnson, Analyt.Chenz., 1961, 33, 106.153 M. Ziegler, 2. undyt. Chenz., 1961, 180, 1 .154 G. Alberti and A. Conte, J . Chronaatog., 1961, 5 , 844.155 M. J. Nunes da Costa and M. A. S. Jerhimo, J . Chromatog., 1961, 5, 456.156 J. P. Adloff, J . Chrcmmtoq., 1961, 5, 366.15’ C. Testa, J . Chronmtog., 1961, 5, 236.158 G. L. Starobineta and S. A. Mechkovskii, Zhur. analit. Khim., 1961, 16, 319.159 W. Rieman, 111, J . Chem. Educ., 1961, 38, 338.160 F. Helfferich, Nature, 1961, 189, 1001.161 P. Chovin, Bull. Soc. china. France, 1961, 875.162 I. G . McWilliam, Rev. Pitre Appl. Chenz. (AustraEia), 1961, 11, 33.163 It. X. Evans and P. G. W. Scott, Natwre, 1961, 190, 710.164 E. M. Bens, Aizulyt. Chenz., 1961, 33, 179.165 D. E. Martire, AnaZyt. Chern., 1961, 33, 1143410 ANALYTICAL CHEMISTRYreducing analysis time are given in a discussion of high-speed gas chromato-graphy.166Lovelock 167 reviews the construction, scope, and application of ionisa-tion detectors.Columns constructed from individual short sections,arranged cylindrically and connected at the ends,168 have advantages in easeof filling, thermostatting in a large Dewar flask, and tapping to give varyinglengths. Circuit details are given for a recording integrator.169 Theeffectiveness of stream-splitters is discussed and a satisfactory design isdescribed. 170 Methods are given for determining gas-chromatographic frac-tions by mass spectrometry,171 chemical reaction,l72 infrared spectro-~ c o p y , ~ ~ ~ , 174 and measurement of radioa~tivity.l7~Improvements have been devised for using gas chromatography in sepa-rating and detecting the permanent gases in general, l~ hydrogen,l77 hydro-gen, nitrogen and oxygen derived from steel and cast iron,178 and impuritiesin chlorine gas.179Materials of low volatility may be identified through their pyrolysis pro-ducts, the chromatogram of which is often specific for the original substance.The technique is particularly applicable to analysis of polymers, and Hewittand Whitham 180 have reviewed the methods employed and have describeda pyrolysis unit which can be attached to a chromatographic column.Otherpyrolysis units have been designed 1 8 1 9 182 and a two-stage gas chromato-graph has been constructed 183 to deal with the products of flash pyrolysisby xenon discharge or carbon arc.In a study of combustion products bygas chromatography lS4 over 20 compounds were separated.Of the many hundreds of applications of gas chromatography to indi-vidual compounds published during the year, mention will only be made ofthe determination of hydrogen cyanide in air samples with a precision andaccuracy superior to those for the usual chemical methods,lE5 and the deter-mination of amino-acids as esters of the N-trimethylsilyl or N-acetylderivatives. lS7166B. 0. Ayers, R. J. Loyd, and D. D. DeFord, Analyt. Chem., 1961, 33, 986.1 6 7 J. E. Lovelock, Analyt. Chem., 1961, 33, 162.1 6 8 s . A. Ryce and W. A. Bryce, Analyt. Chem., 1961, 33, 654.160 A. P. H. Jennings, J . Sci. Instr., 1959, 38, 55.1"JL.S. Ettre and W. Averill, Analyt. Chem., 1961, 33, 680.171E. J. Levy, R. R. Doyle, R. A. Brown, and F. W. Melpolder, Analyt. Chem.,172 R. Rowan, jun., Analyt. Chem., 1961, 33, 658.173 J. Haslam, A. R. Jeffs, and H. A. Willis, Analyst, 1961, 86, 44.174 S. S. Chang, C. E. Ireland, and H. Tai, Analyt. Chem., 1961, 33, 479.176A. T. James and E. A. Piper, J . Chromatog., 1961, 5, 265.176R. A. Landowne and S. R. Lipsky, Nature, 1961, 189, 571.177 P. J. Kipping, Nature, 1961, 191, 270.1 7 8 P . Tyou and A. Hans, Rev. Mttall., 1961, 58, 187.179 J. Lacy and K. G. Woolmington, AnaZyst, 1961, 86, 350.18oG. C. Rewitt and B. T. Whitham, Analyst, 1961, 86, 643.181W. B. Swann and J. P. Dux, Analyt. Chem., 1961, 33, 654.1E2H. Cherdron, L.Hohr, and W. Kern, Angew. Chern., 1961, 73, 215.l a 3 S. B. Martin and R. W. Ramstad, Analyt. Chem., 1961, 33, 982.1a4C. F. Cullis, A. Fish, F. R. F. Hardy, and E. A. Warwicker, Chem. and Id.,lE5 K. G. Woolmington, J . Appl. Chem., 1961, 11, 114.la6K. Ruhlmann and W. Giesecke, Angew. Chem., 1961, 73, 113.15'D. E. Johnson, S. J. Scott, and A. Meister, Analyt. Ghem., 1961, 33, 669.1961, 33, 698.1961, 1158CARTWRIGHT, WESTWOOD, AND WILSON 41 16. Gravimetric and titrimetic analysisGravimetric Analysis.-Although classical gravimetry continues to loseground in the face of instrumental methods, some analysts remain who havenot yet abandoned their crucibles. Some new reagents have been proposed,mainly in the inorganic field, and some established methods have beenre- appraised.Inorganic.Gravimetric and titrimetric methods for the determinationof gold have been surveyed and critically examined,l*8 and a similar examina-tion has been made of the gravimetric methods for the determination ofphosphorus in tungsten ~tee1s.l~~New reagents have been reported for the detection and gravimetric deter-mination of the alkali metals. 5-Benzaminoanthraquinone-2-sulphonic acidis very sensitive to the presence of sodium but is not selective and is unableto tolerate the presence of other alkali metals or the ammoniumOrotic acid yields soluble salts with ammonium and substituted ammoniumbases which precipitate sodium and potassium orotates.lgl NN-Dialkyl-2-hydroxyethylammonium orotates can be used for the gravimetric deter-mination of sodium and potassium in the absence of each other but in thepresence of ammonium ions.Beryllium may be determined by precipitation a t 50-60" and pH 5.5-6.5 with ethanolic N-benzoyl-N-phenylhydroxylamine ; lg2 the precipitatemay be weighed directly or after ignition to oxide.Separation of berylliumfrom iron, aluminium, and titanium may be accomplished by differentialprecipitation.Silicon has been determined in the presence of boron by dehydration ofsilicic acid with glycerol and precipitation with gelatine.lg3 The resultshave been found to be as good as or better than those obtained by conven-tional mineral-acid methods.Small quantities of lead in solution ( 1 4 mg.) may be quantitativelyreduced to the metal by a chromous salt at pH 3-7 and may be filtered offand weighed.lg4A number of carboxylic acids have been used for the precipitation ofthorium;lg5 o-bromobenzoic acid a t pH 3434.2 is useful for the separationof thorium from rare earths.Zirconium may be determined by precipita-tion with 3-acetyl-4-hydroxycoumarin at pH 3.5-7.0, and the same reagentprecipitates titanium lg6 at pH 7-0-9.0. In both cases the precipitates areignited to oxide.A study has been made of the coprecipitation of phosphate with leadlesF. E. Beamish, Talanta, 1961, 8, 85.leg 5. Spauszus, C. Schwarz, and H. J. Weigel, 2. analyt. Chem., 1961, 182, 184.lQoH. S. Gowda, and W. I. Stephen, Analyt. Chim. Acta, 1961, 25, 163.lS1R. Selleri and 0. Caldini, Andyt.Chem., 1961, 33, 1944.lea J. Das and S. C. Shome, Analyt. Chim. Acta, 1961, 24, 37.lQ3L. C. Pasztor, Analyt. Chem., 1961, 33, 1270.lQ4N. T. Vasina, Zhur. analit. Khirn., 1961, 16, 241.lg5 Ch. Bheemasankara Rao, P. Umapathi, and IT. Venkateswarlu, Analyt. Chim.lQ6 A. N. Bhat and B. D. Jain, Proc. Indian Acad. Sci., A , 1961, 53, 147.Acta, 1961, 24, 391412 ANALYTICAL CHEMISTRYmolybdate in the British Standards Institution method for determiningphosphorus in ~tee1.1~7Molybdenum may be precipitated with N-benzoylphenylhydroxyl-amine lg8 and either weighed directly or as oxide after heating to 500-525".The method may be used in the presence of chromium(vI), cobalt(=),nickel( II) , copper( 11) , iron( III) , and vanadium( v) .The determination of cobalt(@ by precipitation as anthranilate and asphosphate has been examined and gravimetric procedures compared withelectrolysis methods.lg9 Of the gravimetric methods only a modificationof the phosphate precipitation gives satisfactory results. The electrolyticmethod gives high results owing to a contaminated deposit.In the determination of the composition of urea-hydrocarboncomplexes urea may be quantitatively precipitated by the addition of asaturated solution of xanthhydrol in methanol ;2O0 the precipitate is weighedafter drying at 100". Three methods for the determination of N-o-bromo-benzyl-N-ethyl-NN-dimethylammonium toluene-p-sulphonate by means ofsodium tetraphenylborate have been examined. 201 The methods consistedof gravimetric, gravimetric followed by a titrimetric determination in non-aqueous solution, and titrimetric in aqueous medium, and were found to giverelative errors of -&0.6%, &0.2%, and &0.7%, respectively.Precipitation from homogeneous solution.The r61e of nucleation in pre-cipitation from homogeneous solution has been discussed following the state-ment by Fischer that the process is one of direct mixing. Haberman andGordon,Zo2 while admitting that this may occur, maintain that it is by nomeans the normal situation, and hold that Fischer's conclusions are notapplicable to many methods of generation of ions in situ. Fischer, whileagreeing that nucleation is not necessarily one of direct mixing, feels thatthere is still sufficient evidence to indicate that this must frequently bethe case.Coprecipitation in some binary sulphate systems has beenstudied. 203The use of hydrazine has been recommended to accelerate the rate ofhydrogen sulphide evolution from thioacetamide solutions. 204 Readily col-lected precipitates of metal sulphides may be obtained by working at 50"and pH 5.5.A study has been made of precipitation at constant pH by using cationrelease from metal-EDTA complexes by oxidation of the metal complexeswith hydrogen peroxide,205 and the method has been applied to the precipi-tation of certain metal phosphates.206The method of Gordon and Firsching for the precipitation of bariumOrganic.lg7 R. B. Heslop and R. Kirby, Analyst, 1961, 86, 134.Is* S. K. Sinha and S.C. Shome, Analyt. Chim. Acta, 1961, 24, 33.lS9 A. G. Foster and W. J. Williams, Analyt. Chim. Acta, 1961, 24, 20.200R. W. Kiser, M. D. Shetlar, and G. D. Johnson, Analyt. Chem., 1961, 33, 314.2e1 I. Gyenes, Magyar Kim. Folydirat, 1961, 67, 162.2ozR. B. Fischer, Analyt. Chem., 1960, 32, 1127; N. Haberman and L. Gordon,%03A. I. Cohen and L. Gordon, Talanta, 1961, 7, 195.204D. M. King and F. C. Anson, Analyt. Chem., 1961, 33, 572.205P. F. S. Cartwright, Analyst, 1961, 86, 688.206 P. F. S. Cartwright, Analyst, 1961, 86, 692.ibid., 1961, 33, 1801; R. B. Fischer, ibid., p. 1802CARTWRIGHT, WESTWOOD, AND WILSON 413chromate at controlled pH has been modified to reduce the time required forprecipitation, and to overcome the need for careful pH contr01.~0~The separation of strontium from calcium and the selective precipitationof strontium sulphate may be achieved by the addition of a solution of mag-nesium sulphate to mixtures of calcium and strontium complexes withEDTA t o displace the strontium.2o8 A similar technique has been appliedby Firsching to the precipitation of barium by displacing the metal fromeither its EDTA or its DCYTA (1,2-diaminocyclohexane-NN"N'-tetra-aminoacetic acid) complex by the addition of magnesium i0ns.~0~ Tetra-fluoroethylene beakers were used to prevent adherence of the precipitate tothe walls of the vessel.Aluminium has been determined as aluminium oxinate by hydrolysis of8-acetoxyquinoline to generate the precipitant in situ,210 and as quinolate bythe volatilisation of acetone from an acetone-water solution.211Niobium oxinate of definite composition has been precipitated by ureahydrolysis in a solution of the metal containing oxalic acid and an excess of8-hydroxyquinoline, 212 and tantalum and niobium have been precipitatedand determined with 3,3',4', 5,7 -pentahydroxyflavanone.Tungsten may be precipitated by the thermal decomposition of solubleperoxytungstates in a nitric acid-hydrogen peroxide solution with less co-precipitation of molybdenum and vanadium.214The precipitation of palladium dimethylglyoximate has been reportedby the generation in situ of dimethylglyoxime from biacetyl and hydroxyl-amine.215 The precipitates were readily filtered, but the separation fromplatinum and nickel was found to be no better than may be achieved byconventional methods.Cobalt has been precipitated by reaction of bivalentcobalt with a mixture of nitrous acid and 2-naphthol to give tervalentcobalt 1 -nitroso-2-naphthoxide, but nickel, copper, and silver interfere. 216Titrimetric Analysis.-This Report is divided according to the class oftitrimetric determination, and reflects the continuing importance of con-tributions to chelatometry, among which are several papers dealing withmore fundamental aspects. Functional-group determinations are againincluded in the section on non-aqueous titrimetry.The theory and practice of titrimetric analysis have beencrit,ically reviewed, and the selection and preparation of primary standardshave been discussed.217 The use of anhydrous sodium carbonate as a stan-dard in acidimetry has been studied and a recommended method has beenproposed for its preparation for this purpose.218General.207 G.Norwitz, Analyt. Chern., 1961, 33, 312.20aL. Ber&k and J. Munich, Coll. Czech. Chern. Comrn., 1961, 26, 276.2osF. H. Firsching, Analyt. Chem., 1961, 33, 1946.210L. C. Howick and W. W. Trigg, Analyt. Chem., 1961, 33, 302.211L. C. Howick and J. L. Jones, Talanta, 1961, 8, 445.21zL. Kosta and M. Dular, Talanta, 1961, 8, 265.213 F. L. Chan, Talanta, 1961, 7 , 253.z14R. Dams and J. Hoste, Talanta, 1961, 8, 664.t l s L . J. Kanner, E. D. Salesin, and L. Gordon, Talunta, 1961, 7, 288.216 A. H. A. Heyn and P. A. Brauner, Talanta, 1961, 7, 281.217 A. Graire, Chirn.Anal., 1961, 43, 53.218 S. J. Cox, W. C . Johnson, E. J. Newman, and J. T. Yardley, Analyst, 1961,86, 4644 14 ANALYTICAL CHEMISTRYBishop and Jennings have continued their work on the use of chlor-amine T with a potentiometric study of the chloramine r-arsenic(m) reac-tioq219 a study of the use of visual indicators in the same reaction,220 andan investigation of the chloramine T-iodate reaction.221A rapid method has been described for the deter-mination of combined ammonia and phosphate in the system diammoniumphosphate and dipotassium phosphate. 222 An alkalimetric method hasbeen used for the determination of phosphoric acid, condensed polyphos-phates being used for masking interfering ions.223 The method depends onthe formation of colourless complexes of sodium hexametaphosphate withcalcium, magnesium, iron, and aluminium which do not interfere with theindicator colour change in alkalimetric analysis.Very small amounts of carbon dioxide may be determined by absorptionin an excess of barium hydroxide solution which is protected from atmo-spheric carbon dioxide by a layer of ~ e n t a n e .~ ~ ~ Results are said to beaccurate within 1.0% and the method may be applied to the determinationof carbon in organic compounds.A study has been made of the iodometric determina-tion of carbon disulphide 225 and attention has been drawn to the importanceof pH control in avoiding low results. The conditions affecting the iodo-metric determination of persulphate in sulphuric acid solution have beenstudied 2z6 and a scheme for the iodometric analysis of chromate, arsenate,periodate, iodate, bromate, and chlorate ions in the presence of one anotherhas been described.227Iodometric methods have been used in the determination of the con-figuration of bridged Diels-Alder adducts.228 endo-Products absorb 99-101% of the theoretical amount of iodine, while exo-isomers do not react.The excess of iodine is titrated with arsenite solution and starch indicator.E’errous ions in ferrous oxalate may be determined by a bromatometrictitration using p-ethoxychrysoidine indicator. 229 Special precautions arenecessary when dissolving the sample to exclude atmospheric oxygen.Persulphate in sulphuric acid solution is hydro-lysed to hydrogen peroxide, the reaction reaching a maximum a t 1 2 .5 ~ -sulphuric acid. Under controlled conditions use can be made of this reac-tion for the determination of persulphate by titration with permanganatesolution. 230Uranium can be determined in the presence of large quantities of ironby the double precipitation of UF4 followed by titration with ceric sul-219E. Bishop and V. J. Jennings, Talanta, 1961, 8, 22.2 2 0 E . Bishop and V. J. Jennings, Talanta, 1961, 8, 34.221E. Bishop and V. J. Jennings, Talanta, 1961, 8, 697.2 2 z B . Paschkes and B. Bernas, Analyt. Chim. Acta, 1961, 24, 5 .2z3 C. Nedorost and J. Brzobohatttjr, Chem. prumsyl, 1961, 11, 79.224 E. Schulek, J. Trompler, A. Endroi-Havas, and I. Remport, Analyt. Chim. Acta,225M.Eusef and M. H. Khundkar, Analyt. Chim. Acta, 1961, 24, 419.Z Z S Y . K. Gupta, 2. analyt. Chem., 1961, 180, 260.227 L. Szekeres, Ann. Chim., R m a , 1961, 51, 200.zzsH. Stockmann, J. Org. C h m . , 1961, 26, 2025.J. Laszlovsky, Pharm. Zentralhalle, 1961, 100, 77,23oY. K. Gupta, Analyt. Chim. Acta, 1961, 24, 415.Acid-base titrations.HaZogen titrations.Other redox titrations.1961, 24, 11CARTWRIGHT, WESTWOOD, AND WILSON 415phate.231 A cerimetric method has been applied to the determination ofmanganese in pyrolusite.232 The material is digested in oxalic-sulphuricacid mixture, filtered to remove silica, and titrated with use of ferroin asindicator.A titrimetric method for the assay of thiols has beendescribed233 in which the sample is dissolved in pyridine, aqueous silvernitrate solution is added, and the mixture is stored for 5 minutes.Wateris then added and the liquid is titrated with sodium hydroxide solution,phenolphthalein being the indicator.A review has been published of some of themost important indicators used in complexometric titrations and thedefinition of an ideal indicator has been discussed.234 The problem ofincreasing selectivity has been reviewed 235 and a method has been des-cribed for selecting the most suitable complexing agent for a particularmetal. 236PKbil and his co-workers have continued their work on basic problemsin complexometry with studies of the determination of thallium,237 themutual masking of iron and the masking of tervalent chrom-the determination of copper and iron,240 and the use of thioglycollicacid as a masking agent.241 Cheng 242 has studied the theoretical aspectsof masking and demasking reactions and has proposed a new term, theselectivity ratio, as an index to predict the possibility of unknown maskingreactions.Many examples of the more particular use of masking agents have beenpublished. In weakly acid solutions cyst eine forms colourless complexeswith certain cations, permitting the determination with EDTA of zinc, lead,nickel, aluminium, and iron in the presence of larger amounts of mercuryor Calcium and magnesium may be determined in the presenceof large amounts of manganese by masking the manganese with cyanide;24*and in the analysis of ferrites, magnesium, lead, and nickel may be sepa-rated by stepwise titration with EDTA using suitable masking agents.245I n the chelatometric determination of calcium it has been found thatsome improvement in the indicating properties of fluorescein may be attainedby mixing it with one quarter of its weight of phenolphthalein complexan.246Calcium and magnesium may be determined in ferromanganese slags after231 T.J. Blalock, U.S. Atomic Energy Comm., Rep. BM-RI-5687, 1959.232 M. R. Verma, S. K. Mathur, P. Dayal, and S. Adwani, 2. analyt. Chetn., 1961,233 B. Saville, Analyst, 1961, 86, 29.234 Z. Lada, Chem. Analit., 1961, 6, 135.235 T. S. West, Analyt. Chint. Acta, 1961, 25, 301.236 E. Wiinninen, Talanta, 1961, 8, 355.237 R. P?ibil, V. Veseljr, and K. Kratochvil, Tulanta, 1961, 8, 52.238 R.Pfibil and V. Veseljr, Talanta, 1961, 8, 270.239 R. Psibil and V. Veseljr, Talantu, 1961, 8, 565.240 R. P?ibil and V. Vesely, TaZanta, 1961, 8, 743.241R. P?ibil and V. Veself, Talanta, 1961, 8, 880.242 K. L. Cheng, Analyt. Chem., 1961, 33, 783.243 W. Berndt and J. $Bra, Tulanta, 1561, 8, 653.244 P. Povondra and R. Pcibil, Coll. Czech. Chem. Comnt., 1961, 26, 311.245 R. Pfibil and V. Vesely, Chenzist-Analyst, 1961, 50, 7 3 .a4aV. Svoboda, V. Chromjr, J. Korbl, and L. Dorazil, Talanta, 1961, 8, 249.Miscellaneous.Chelatometric titrations.180, 181416 ANALYTICAL CHEMISTRYthe removal of manganese by precipitation with potassium chlorate in nitricacid solution, and masking of iron, aluminium, and titanium with tri-ethanolamine. 247 The limits of interference by iron, manganese, aluminium,and phosphate in the EDTA determination of calcium in the presence ofmagnesium by means of Cal-red indicator have been investigated.248The complexometric determination of aluminium has been studied.249In the recommended method aluminium is boiled with excess of EDTA andthe excess is titrated with a standard lead solution.Sodium fluoride is thenadded to liberate EDTA equivalent to the aluminium present, and theliberated EDTA is titrated with lead solution, methyl thymol blue being theindicator. Methods for the indirect titration of thallium with EDTA in thepresence of iron or bismuth have been given,250 and the direct determinationof thallium in monocrystals of alkali-metal halides by EDTA titration atpH 3.8 using Xylenol Orange indicator has been rep0rted.2~1Two indicators, Acid Chrome Dark Blue (C.I.Mordant Blue 7) and AcidChrome Blue K, have been used in the EDTA titration of lead.Z52 Thesensitivity of both indicators in alkaline tartrate solution is greater thanthat of Chromogen Black ET-100 (C.I. Mordant Black 11). Silicic acid oralkaline silicates may be precipitated with cobalt(n) and the excess cobalttitrated with EDTA by using a mixed indicator (Eriochrome Black T andTropaeolin 00) for the indirect determination of the silicicZirconium may be determined in sulphuric acid solution by direct titra-tion with EDTA solution and Xylenol Orange as indicator;254 no inter-ference is caused by aluminium, lanthanum, cerium, zinc, cadmium, man-ganese, magnesium, chloride, nitrate, or molybdate, or by iron, indium,scandium, thorium, yttrium, nickel, or cobalt in amounts not greater than10 mg.Interference is caused by bismuth, phosphate, fluoride, and oxalate.Thorium may be titrated with EDTA at pH 1.6-3-0 with Chrome Azurol S(C.I. Mordant Blue 29) as indicator,255 or in the pH range 2.0 to 2.7 usingg alloc y anine indicator (dime t hylamino h y drox yp henoxy az onecar box y li cA method has been described for the rapid determination of phosphorusin coal.257 After ashing, the phosphate is precipitated as magnesiumammonium phosphate and the phosphate content is determined indirectlyby titrating the magnesium with EDTA solution and Eriochrome Black Tas indicator.The existence of a 1 : 1 complex of vanadyl(v) with EDTA has beenestablished from conductometric measurements and has been made the basis247 A.G. C. Morris, Analyt. Chem., 1961, 33, 599.248 P. Moss, J . Sci. Food Agric., 1961, 12, 30.249 0. Budevski and L. Simova-Filippova, Com,pt. rend. Acad. Bulg. Sci., 1961,250A. I. Busev and V. G. Tiptsova, Zhur. analyt. Khim., 1961, 16, 275.Z51 M. Kratochvil and J. Blecha, Chemist-Analyst, 1961, 50, 11.25% T. B. Styunkel’ and Z. A. Mikhaleva, Trudy Ural’sk. Politekh. Inst., 1960, 169;253 J. Jenik, Chem. prumysl, 1961, 11, 188.254 A. E. Klygin and N. S. Kolyada, Zavodskaya Lab., 1961, 27, 23.255 S . P. Sangal and A. K. Dey, 2. analyt. Chem., 1961, 178, 415.Z56S. P. Sangal and A.K. Dey, J. Indian Chem. SOL, 1961, 38, 75.257 A. C. Bhattacharyya, B. P. Bhaduri, and N. G. Banerjee, Analyst, 1961, 86, 195.14, 179.ref. Zhur. Khim., 1961, Abstr. No. 5073CARTWRIGHT, WESTWOOD, AND WILSON 41 7of a volumetric method for the determination of ~anadium.~5* The com-plexometric titration of uranium(rv) with EDTA is possible at pH 1.0-1.8by using thoron as the indi~ator.2~9 A study of the effect of other elementshas shown that thorium, cerium(Iv), and iron(=) interfere at a ratio of10 to 1, and that cobalt, copper, bismuth, mercury(n), vanadium, andfluoride hinder the titration.In the complexometric determination of iron it has been found thatN-benzoylphenylhydroxylamine (0.5% in acetone), phenylhydroxamic acid(3% aqueous), and sulphophenylhydroxamic acid (3% aqueous) all formred-violet complexes with iron(m) at pH 1-14, and can be used as indi-cators in EDTA titrations.260An unusual application of EDTA has been described by Beck,261 whohas reported that EDTA is oxidised in sulphuric acid or perchloric acidmedium by potassium permanganate but that no oxidation occurs whenEDTA is complexed with a metal ion.This fact has been applied to theindirect determination of bismuth and iron by adding an excess of EDTAto the solution of metal and back titrating the excess of complexing agentwith potassium permanganate solution.Chelatometric methods have been applied to the analysis of organo-metallic compounds.262 Thus aluminium alkyls may be decomposed withhydrochloric acid, the resulting aluminium chloride complexed with excessof EDTA, and the excess titrated with copper sulphate solution, withCatechol Violet as indicator.Non-aqueous titrations and functional-group determination.Develop-ments of indicators for non-aqueous acid-base titrations in the period 1959-1961 have been reviewed.263 The use of certain redox indicators in non-aqueous cerimetry has been s t ~ d i e d . ~ 6 ~ Some indicators used in aqueoussolution have been found satisfactory for the titration of quinol in glacialacetic acid. Sharp changes have been obtained with ferroin, diphenylamine,Methyl Red, and Janus Green, but the last two did not give reversiblechanges. Phenosafranine and Neutral Red were unsatisfactory. ‘Trifiuoromethanesulphonic acid has been used as a titrant in glacialacetic acid solutions and its performance has been compared with that ofperchloric a~id.~65 The only advantage offered is the freedom from pre-cipitate formation, and it is doubtful whether this alone is sufficient to justifythe use of the reagent in view of its high cost.Dimethylformamide may be purified for use in non-aqueous titrationsby treatment with Dowex 1-XI0 (OH- form) in a stoppered flask for severalhours.266268 G. Kakabadse and H. J. Wilson, Analyst, 1961, 86, 402.s6aP. N. Palei and Li-Yuan’ Hsu, Zhur. analit. Khim., 1961, 16, 51.a601. P. Alimarin and Tsz6 Yun’-Syan, Vestn. Moskow Univ., Ser. Khim., 1961,261 M. T. Beck, Chemist-Analyst, 1961, 50, 14.262 C. Hennart, Chim. Anal., 1961, 43, 283.263 W.C. Purdy and J. T. Stock, Chemist-Analyst, 1961, 50, 88.264G. P. Rao and A. R. Vasudevs Murthy, 2. analyt. Chem., 1961, 180, 169.2s5E. S. Lane, Talanta, 1961, 8, 849.266 R. E. Moskalyk, L. G. Chatten, and M. Pernarowski, J. Phurm. Sci., 1961, 50,No. 1, 59.179.418 ANALYTICAL CHEMISTRYMixtures of sulphuric acid and sulphonic acid may be determined bydifferential titration in acetone medium,267 using it solution of tetraethyl-ammonium hydroxide in benzene and methanol as the titrant, and a visualindicator consisting of a mixture of Neutral Red and thymolphthalein.Sulphate has been determined indirectly in the presence of interfering ionsby precipitation with excess of barium acetate and back titration of theexcess with perchloric acid in glacial acetic acid by a potentiometricmethod. 268Alkoxyl groups have been determined by absorption in pyridine anddirect titration with tetrabutylammonium hydroxide.269Primary and secondary amines have been determined with perchloricacid in acetic and the same reagent has been used for the titrationof organic bases and alkali-metal salts of organic acids.271 Basic compoundscontaining mercapto- or sulphide groups can be titrated with perchloric acidin acetic acid in the presence of mercuric acetate.272The rapid determination of organic hydroxyl groups has been des-cribed.273 The method is described for primary and secondary alcohols butmay also be applied to the determination of polyols, sugars, phenols, primaryand secondary amines, and some oximes.Sodium citrate and sodium potassium tartrate may be assayed by cationexchange in aqueous solution followed by titration in non-aqueous solu-tion.274 Kojic acid has been assayed by a non-aqueous titration using potas-sium methoxide in benzene-methanol as the titrant with Azo Violet indi-cator, and the use of kojic acid in the gravimetric determination of zinc hasbeen described.275Tetracyanoethylene has been used to determine aliphatic, alicyclic, andaromatic 1,3-dienes.276 The diene is allowed to react with an excess of thereagent in dichloromethane and the excess is titrated with cyclopentadienein ethanol.7.Instrumental end-point determinationsConductometric, amperometric, coulometric, potentiometric, and high-frequency methods in titrimetry are dealt with in this section.By far themost popular of these is still the potentiometric method, which with itsrelatively simple apparatus has accounted for more applications than allother end-point methods combined. Comparatively little development hasoccurred in conductometric or high-frequency methods owing to their lackof specificity. Coulometric methods have been increasingly used and thedevelopment of commercial potentiostats in this country will probablyZ67E. A. Gribova, Zavodskaya Lab., 1961, 27, 154.268 G. Goldstein, 0. Menis, and D. L. Manning, Analyt. Chem., 1961, 33, 266.269R. H. Cundiff and P. C. Markunas, Analyt. Chem., 1961, 33, 1028.2 7 O M . Rink and R. Lux, Arch. Pharm., 1961, 294; Mitt.deut. pharrn. Ges., 1961,271 M. Rink and R. Lux, Apoth.-Ztg., 1961, 101, 911.272 I. Bayer and E. Posgay, P h a m . Zentralhlle, 1961, 100, 65.273 W. T. Robinson, jun., R. H. Cundiff, and P. C. Markunas, Analyt. Ghern., 1961,27aM. L. Richardson, Analyt. Chim. Acta, 1961, 24, 46.276 C. Lents and W. Wagner, Chemist-Analyst, 1961, 50, 43.27aM. Ozolins and G. H. Schenk, Analyt. Chem., 1961, 33, 1035.31, 117.33, 1030CARTWRIGHT, WESTWOOD, AND WILSON 419result in an increased flow of applications a t controlled potential. Auto-matic titrimeters are being increasingly used and lend themselves to routinework. Thus the automatic titrator described by Haslam, Hamilton, andSquirrell 277 for elementa.1 analyses, where the whole process is done byautomatic control, gives an indication of things to come.In view of its increasing use a small sub-section has been devoted tochronopotentiometry.Although in a sense it is a coulometric method atconstant current, it utilises a rapid change of potential to signify the end ofthe process, the titrant being generated electrolytically. The transitiontime is the important measurement and a potential-time graph-the chrono-potentiogram-is obtained, First investigated by Delahay and Mam-antov 278 and based on an earlier sugge~tion,2'~ development of the methodhas been largely confined to the United States of America. A lack of readilyavailable constant- current devices has probably deterred analysts in thiscountry from testing the capabilities of this technique.A special mention should be made of the new technique put forward byBishop, 280 differential electrolytic potentiometry.The method consistsessentially of passing a minute but heavily stabilised current across a pairof stationary electrodes immersed in the titration solution and measuringthe potential developed across them. The electrodes behave independentlyand, when compared with an indicator electrode, one leads and the otherlags behind the indicator potential. If one species is not reversibly electro-lysed its potential remains more or less steady but the other shows a sig-nificant change in potential. The end-point is indicated, under appropriateconditions, by a very sharp peak in the potential-titre curve. Mention ismade of its application to very dilute solutions.Conductometric.-No significant developments have occurred in thistechnique over the last few years, and the number of papers is decreasing.This is inevitable in view of its lack of specificity and the superiority of othermethods particularly for determining increasingly small amounts.Anautomatic conductometric titrator has been described in which the con-ductance is recorded as a function of the titrant added, and is claimed togive a linear response up to 2.6 x lo4 ,umhos.281 A four-electrode assemblyinvolving a differential system has been applied to the determination ofcarbon dioxide and ammonia in scrubbing water for coke-oven gas.282Several flow systems involving conductometric measurements have beenused for elemental analyses.Thus the absorption cells devised by Green-field 283 and Stuck 284 for the micro-determination of carbon in organiccompounds after combustion utilise changes in conductance of alkali solu-tions. An absorption device is similarly used to determine carbon dioxidein air,285 and an indirect method for the continuous determination of2 7 7 J. Haslam, J. B. Hamilton, and D. C. M. Squirrell, Analyst, 1960, 85, 556.278P. Delahay and G. Mamantov, Analyt. Chem., 1955, 27, 478.279L. Gierst and A. Juliard, J. Phys. Chem., 1953, 57, 701.280 E. Bishop, Mikrochim. Acta, 1956, 619.281 D. W. Colvin and R. C. Propst, Analyt. Chem., 1960, 32, 1858.282E. Barendrecht and N. G. Janssen, Analyt. Chem., 1961, 33, 199.283 S. Greenfield, Analyst, 1960, 85, 486.284W.Stuck, Mikrochim. Acta, 1960, 421.285 I. Holm-Jensen, Analyt. Chinz. Acta, 1960, 23, 13420 ANALYTICAL CHEMISTRYacetaldehyde in aqueous liquid streams uses the sulphurous acid liberatedduring the SchB’s test.286Fifteen metal acetates have been successfully titrated with trichloro-acetic acid in aqueous solution,287 though some, mostly those of bivalentmetals, require the presence of 50% ethanol for reasonable end-points. Alarge number of weak bases, with ionisation constants between 10-8 and10-l2, have also been titrated with a similar titrant in 50% ethano1.288Formation of a 1 : 1 complex between vanadium(v) and EDTA has beendemonstrated 258 provided that the pH is >1.8 and [H+]/[Vv] is >5.Thorium, on the other hand, shows two inflections in the titration curvecorresponding to Th : EDTA = 1 : 1 and 1 : 2 respecti~ely.~8~ A criticalstudy has been made of the formula of ammonium phospho-l2-molybdateunder a variety of conditions of acidity, temperature, and concentrations ofreactants.290 The precipitate after solution in alkali is titrated with acidto reprecipitation.Micro-determination of sulphur in organic compoundsby the oxygen flask method has been elegantly carried out by titration wit,hbarium acetate. By prior neutralisation of the acids formed, only thesulphate is titrated and chloride does not interfere. Phosphate, if present,can be similarly eliminated by precipitation with silver nitrate.291Titrations have also been carried out in non-aqueous solutions.A num-ber of metal oxinates have been successfully determined in ethylenediaminesolutions with potassium methoxide in the same solvent,292 although a fewmetals, such as iron, thallium, and lanthanum, gave useless end-points.Sulphonates and phenoxates of calcium and barium, used as detergents inlubricating oils, have been determined directly in benzene-ethanol (1 : 1)mixtures by titration with a strong acid.293Czesium chloride has been titrated with antimony trichloride in a glacialacetic acid medium. 294Amperometric.-This continues to be a popular technique and has beenreviewed by Laitinen.295 A theoretical study has been made by Smit, whohas considered the cases of one- or two-indicator electrodes and has derivedrelationships between the current and concentration for reversible and irre-versible processes.296 Most of the work has been carried out with the con-ventional dropping mercury or rotated platinum electrodes but there hasbeen some tendency to use other indicating systems.Kolthoff et al. haveused the rotated aluminium electrode successfully for fluoride ion downto 10-5~,297 and rotated silver electrodes have been similarly used to deter-2 8 6 1 . A. Capuano, Analyt. Chem., 1960, 32, 1025.2 8 7 F. Gaslini and L. Z. Nahum, Analyt. Chim. Acta, 1961, 24, 79.2 8 8 F . Gaslini and L. Z. Nahum, Analyt. Chem., 1960, 32, 1027.289 V. T. Athavale, S. C. Saraiya, and A. K. Sundaram, Analyt. Chim. Acta, 1960,29’3P. Cannon, Talanta, 1960, 3, 219.291 J. P. Dixon, Analyst, 1961, 86, $97.2e2E.E. Underwood and A. L. Underwood, Talanta, 1960, 3, 249.293 J. Larbre and J. Briant, Rev. Inst. franc. PBroZe, 1960, 15 (7-8), 1170.se4 J. HaviP, Coll. Czech. Chem. Comm., 1960, 25, 695.296H. A. Laitinen, Analyt. Chem., 1960, 32, 180R.298 W. M. Smit, Chem. Weekblad, 1960, 56, 25.2871. M. Kolthoff and C. J. Sambucetti, Analyt. Chim. Acta, 1960, 22, 253; I . M.23, 200.Kolthoff, E. J. Meehan, and C. J. Sambucetti, ibid., p. 351CARTWRIGHT, WESTWOOD, AND WILSON 421mine cyanide ion down to a level of 10-8 g. in 7 ml. in the presence of athousand-fold excess of other ions.298Combinations of amperometry with other techniques have appeared.By using a square-wave generator, mixtures of ferrous and ferric ions werefirst complexed with EDTA and the ferrous complex was titrated with ferro-cyanide. The slopes of the current-voltage polarisation curves were usedfor end-point detection.299 By means of a combined dead-stop ampero-metric method, thallium ions were titrated in hydrochloric acid solution withpotassium iodate or with permanganate in the presence of bromide.300 Anautomatic coulometric-amperometric titrator giving direct readings in milli-equivalents of chloride per litre on a 0.1 ml.sample has been reported foranalysis of blood serum.3o1A number of metals have been determined by using EDTA as titrant.Zirconium has been titrated at a rotated tantalum electrode at f-1.2 v(S.C.E.) with little interference from other ions.302 However, in a recentreview by Milner and Edwards on the analytical chemistry of zirconium,303other amperometric methods are discussed and it is concluded that titri-metric methods involving indicators are probably preferable.Indium, asthe perchlorate, has been determined at pH 4-6 down to 5 x 1 0 - 5 ~ ~ con-~ e n t r a t i o n , ~ ~ ~ and thorium has been determined in monazite sand, afterremoval of the rare earths with oxalic acid, at +0.4 to +0*5 volt.305 Astudy has been made of EDTA as a titrant for metals at mercury and copperindicator electrodes. The results indicate that the electrode processes occurmuch faster in acid than alkaline solution.306 Arsenic and antimony canbe determined in one solution by using the rotated platinum ele~trode.~O'By titration with iodine at +0.2 v (S.C.E.) the two metals can be deter-mined, but in a similar solution after addition of 1.5 equivalents of the iodineneeded, the arsenic only is determined under the same conditions.Some novel titrants used in amperometry for the determination of metalsinclude tartrazine for zirconium 308 and the ammonium salts of benzene- andnaphthalene-selenonic acids, which are claimed to be very selective pre-cipitants for bismuth.309 Tetraphenylborate has been used for potassium,and is claimed to be more flexible and rapid than any other titrimetricmethod.310A recent adaptation ofthe titration with silver nitrate of chlorides, bromides, and iodides, singlyThe methods devised for anions are much fewer.298 J. A. McCloskey, Analyt.Chem., 1961, 33, 1842.299 L. C. Hall and D. A. Flanigan, Analyt. Chem., 1961, 33, 1495.300B. Sharma, Bull. Chem. SOC. Japan, 1960, 33, 277.301E. Cotlove and H. H. Nishi, CLin. Chem., 1961, 7, 285.302 V. A. Khadeev and F. F. Kvashina, Izv. VGssh. Ucheb. Zavedenii Khim. i Khim.303 G. W. C. Milner and J. W. Edwards, Analyst, 1960, 85, 86.304 J. Doleial and J. Z+ka, Coll. Czech. Chem. Comm., 1961, 26, 1464.305 P. N. Palei and N. I. Udal'tsova, Trudy Kom. analit. Khim., Akad. NaukS.S.S.R.,306 G. GuBrin, J. Desbarres, and B. Tremillon, J . EZectroanalyt. Chem., 1960, 1, 226.307V. A. Zakharov, 0. A. Songina, and N. A. Dragavtseva, Zavodskaya Lab.,308 G. Popa, D. Negoiu, and G. Baiulescu, Analyt. Chim. Acta, 1960, 22, 200.300V. S. Sotnikov and I.P. Alimarin, Talanta, 1961, 8, 588.310D. L. Smith, D. R. Jamieson, and P. J. Elving, Andyt. Chem., 1960, 32, 1253.Tekhnol., 1960, 3, 251.1960, 11, 299.1960, 26, 537422 ANALYTICAL CHEMISTRYand in mixtures, to the micro-determination of the combustion products oforganic compounds is claimed to be more rapid and accurate than existingmethods.311 After combustion, sulphur in petroleum products can be deter-mined as sulphide with mercuric chloride, down to 5 p.p.m. on a 0.2 g.sample. 312I n the organic field, the thiol group in cysteine, glutathione, and thio-glycollic acid has been determined a t the rotating platinum wire electrodeby argentimetric and mercurimetric titrations 313 and also by the rotateddropping mercury electrodeY3l4 ethylmercuric chloride being used as titrant.Penicillin, after conversion into penicillamine, has been determined, via itsSH group, with mercuric chl0ride.31~Aromatic aldehydes have been titrated with 2,4-dinitrophenyl-hydrazine, 316 and acetaldehyde with hydroxylamine hydrochloride, 317 withlittle interference from other compounds such as acetone. Glucose, fructose,and saccharose have been determined by ceric perchlorate at a platinum-wire indicator electrode at zero potential in a perchloric acid base elec-t r ~ l y t e .~ ~ ~Lead tannate, catecholate, and pyrogallolate have been successfullytitrated with dilute nitric acid, and the method has been applied to theanalysis of black wattle. 319Coulometric.-This technique is gaining ground although developmentsin Britain are slow, largely owing to lack of suitable industrial instruments.A comprehensive review by Lewis, 320 which clearly illustrates the possi-bilities of controlled-potential and constant-current methods, may provide astimulus for its further development. Other reviews 32l9 322 illustratedevelopments which have occurred abroad and discuss factors which mustbe considered for accurate results.Potentiostats are now available commercially, and the recent electronicdevice of Wadsworth 323 is fully transistorised with a wide range of availablecurrents ; although produced for electrodeposition analysis, it is eminentlysuitable for coulometric work.Similarly, the more elaborate multipurposeapparatus of Herringshaw and Halfhide is appli~able.~24 An instrumenthas been devised for phase analyses of large metallurgical samples,325 anda comprehensive titrator with integrator and automatic cut-off has beendevised for micro-quantities of metals.326 Circuits have also appeared for311s.Greenfield, R. A. D. Smith, and I. L. Jones, Mikrochim. Acta, 1961, 420.312 E. C. Schluter, E. P. Parry, and G. Matsuyama, Analyt. Chem., 1960, 32, 413.313 I. M. Kolthoff and J. Eisenstiidter, Analyt. Chim. Acta, 1961, 24, 83, 280.3l4 W. Stricks and S. K. Chakravarti, Analyt. Chem., 1961, 33, 194.3l5 J. Grafnetterovii, Cas. Le'E. Ces., 1960, 99, 182.3113 A. Berka, J. Doleial, J. Janata, and J. Z$ka, Anulyt. Chim. Acta, 1961, 25, 379.317 R. E. van Atta, W. W. Harrison, and D. E. Sellers, Anulyt.Chem., 1960,32, 1548.31'3E. MichaIski, K. Czarecki, and M. Ignczak, Tatanta, 1960, 5, 137.31s S. E. Drewes, Analyst, 1961, 86, 104.32oD. T. Lewis, Analyst, 1961, 86, 494.321 D. D. De Ford, Analyt. Chem., 1960, 32, 31R.32% E. Barendrecht, Chem. Weekblud, 1960, 50, 37.323N. J. Wadsworth, Analyst, 1960, 85, 673.324 J. F. Herringshaw and P. F. Halfhide, Analyst, 1960, 85, 69.325Yu. A. Klyachko, Yu. D. Labut'ev, and V. A. Mil'chev,326M. T. Kelley, H. C. Jones, and D. J. Fisher, Tulanta, 1960, 6, 185.'Zawodskuya Lab.,1960, 26, 217CARTWRIGHT, WESTWOOD, AND WILSON 423constant-current devices 3279 328 but little of significance has been publishedover the last two years on cell coulometers or current-integrating devices.The majority of papers have been devoted to inorganic applications withcontrolled potentials using instruments already reported.Several appli-cations to metals of importance in the nuclear-energy field have appeared.Uranium has been determined in the presence of thorium by an oxidationprocedure whereby U(IV) is oxidised to U(VI) a t +1.4 v (us. Ag/AgC1),329or reduced in a tripolyphosphate and sulphate base solution whereby molyb-denum and other metals do not interfere.33u A similar procedure has beenused to determine the osygen/uranium ratios in oxides of urani~m.~3lPlutonium in amounts down to 50 pg. has been determined,326 and a reduc-tion of PU(VI) with electrogenerated iron(@ has been reported. 332 Iron,in 2--6~-hydrochloric acid, has been determined by electrolytic oxidationafter a preliminary reduction to Fe(rr) with zinc or other metals.Themethod is claimed to give highly consistent results on standard samples,and manganese, chromium, and titanium do not interfere.333 Tin hasbeen determined as Sn(n) in a bromide medium at a mercury or tin analgamelectrode at -0-70 v (S.C.E.) 334 down to 20 mg. with an error of <0*3%;addition of tartrate prevents interference from antimony and copper. Ina methanolic tetraethylammonium bromide solution, europium and ytter-bium have been determined, at separate potentials, down to 0.5 , ~ e q u i v . ~ ~ ~By using a silver-plated platinum anode, chloride has been determined atvery low concentrations and the method is claimed to be more accurateand to require less sample than other methods.336 The system utilises anadditional silver electrode to act as sensor and the electrolysis is madeautomatic.Small amounts of iodides in the region of 30-100 pg. havealso been determined by an internal electrolysis method 337 with a platinumgauze anode and a lead dioxide-sulphuric acid paste cathode contained in anextraction thimble. Standard solutions of perchloric acid in methyl cyanidehave been prepared by coulometric oxidation of hydrogen in a 0.1M-SOdiUII1perchlorate solution, 338 and a technique using an ion-exchange membranehas been employed to generate a number of standard reagents which areotherwise tedious to prepare. 339 Novel applications include coulometricreduction of cuprous sulphide films on co~per,~*O suitable for up to 15pg./cm.2of sulphur, and to the investigation of the surfa.ce oxidation of platinumand g0ld.3~1327 T.Takahashi and H. Sakurai, Talanta, 1960, 5, 205.328 J. R. Glass and E. J. Moore, Analyt. Chem., 1960, 32, 1265.339 C. M. Boyd and 0. Menis, Analyt. Chern., 1961, 33, 1016.330 H. E. Zittel, L. B. Dunlap, and P. F. Thomason, AnaZyt. Chem., 1961, 33, 1491.331R. W. Stromatt and R. E. Connally, Analyt. Chem., 1961, 33, 345.338 W. D. Shults, Analyt. Chem., 1961, 33, 15.333P. S. Farrington, W. P. Schaefer, and J. M. Dunham, Analyt. Chem., 1961, 33,3JaA. J. Bard, Andyt. Ch;m. Acta, 1960, 22, 577.336E. N. Wise and E. J. Cokal, AnaZyt. Chem., 1960, 32, 1417.33sD. M. Coulson and L. A. Cavanagh, Analyt. Chem., 1960, 32, 1245.337 J. Kis and C.Schejtanow, Periodica Polytech., 1960, 4, 163.338 J. Vedel and B. TrArnillon, J . Electroanalyt. Chem., 1960, 1, 241.339R. B. Hanselman and L. B. Rogers, Analyt. Chem., 1960, 32, 1240.340 T. P. Hoar and C. D. Stockbridge, Electrochim. Acta, 1960, 3, 94.341H. A. Laitinen, Analyt. Chem., 1961, 33, 1458.1318424 ANALYTICAL CHEMISTRYApplications to organic systems are few. Ascorbic acid has, however,been determined at pH 6-03 and +1.090 v (S.C.E.), in the 15-100 mg.range, with an accuracy of h0.7 mg.342 Reaction of hydrazine and disub-stituted hydrazines by electrogenerated bromine has shown that six equiva-lents of bromine are consumed by the unsymmetrically disubstituted com-pounds, whereas hydrazine consumes four.The symmetrical compounds,however, do not behave stoicheiometrically. 343 Thymol has been deter-mined in Thymus vulgaris with electrogenerated bromine with an accuracyof &0-5% on a 0.5 mg. quantity.344With constant-current procedures, applications have been almost exclu-sively inorganic. Iron has been determined with electrogenerated brominein an acetic acid-acetate medium containing b r ~ m a t e , ~ ~ ~ but other media,e.g., sulphuric acid, were not suitable. From 2 to 13 mg. of platinum weredetermined to &06% by stannous ions produced electrolytically in asolution of high bromide c0ntent.3~6It is claimed that silver, nickel, and gold have been determined to a fewparts per thousand by constant-current generation of cyanide ions.347Permanganate produced coulometrically has been used to determine hydro-gen peroxide,348 and ferrocyanide and iodide i0ns.3~~ Fluoride has beentitrated as a base in acetic anhydride containing sodium perchlorate whereinperchloric acid is generated.350A novel method, called voltage-scanning c0ulometry,3~1 in which avoltage sweep is made between two electrodes, has been claimed to deter-mine traces of iron down to 0.025 pg.The peak current flowing is a measureof the amount of iron present.Potentiometric.-This continues to be the most popular method ofelectrometric end-point determination and accounts for more published workthan all other procedures combined. It frequently uses conventional elec-trodes with a pH meter or other simple polarising device.Recent reviewsdiscuss developments in methods s52 and application in non-aqueous solu-tions,353 and a comparison has been made with amperometric methods.354Constructional 355 and mathematical 356 methods for determining equiva-lence points have been discussed where these are not readily ascertainable.Theinstrument of Haslam, Hamilton, and Squirrel1 277 has been used for poten-34aK. S. V. Santhanam and V. R. Krishnan, Analyt. Chem., 1961, 33, 1493.343E, C. Olson, Analyt. Chem., 1960, 32, 1545.344 2. Kalinowska, Acta Polon. Pharm., 1960, 17, 153.345T. Takahashi and H. Sakurai, Talanta, 1960, 5, 205.346A. J. Bard, Analyt. Chem., .1960, 32, 623.347 F. C. Anson, K. H. Pool, and J. M. Wright, J. Electroanalyt. Chem., 1961, 2, 237.348P.S. Tutundiic and M. M. Paunovib, Analyt. Chim. Acta, 1960, 22, 291.349 P. S. Tutundiic, N. M. Paunovid, and M. M. Paunovid, Analyt. Chim. Acta, 1960,3 5 O W . B . Mather and F. C. Anson, Analyt. Chem., 1961, 33, 132.351 F. A. Scott, R. M. Peekema, and R. E. Connally, Analyt. Chem., 1961, 33,352 C. N. Reilley, Analyt. Chem., 1960, 32, 185R.353 J. A. Riddick, Analyt. Chem., 1960, 32, 172R.354 H. L. Kies, Chem. Weekblad, 1960, 56, 13.355 C. Liteanu and D. Cormos, Talanta, 1960, 7 , 25, 32.356 J. M. H. Fortuin, Analyt. Chim. Acta, 1961, 24, 175.A number of automatic recording titrators have been reported.22, 345.1024CARTWRIGHT, WESTWOOD, A N D WILSON 425tiometric work, and a modification of the Precision Dow recording titratorhas made it applicable to amperometric, conductometric, photometric, andthermometric uses.357 Other automatic instruments involve devices toslow down the rate of addition of titrant near the e n d - p ~ i n t .~ ~ ~ , 359 Graphiteelectrodes have been used for applications where others are unsuitable;considerably greater changes of potential occur at the end-point than withthe hydrogen electrode.360Most inorganic applications to metal ions involve oxidation titrations.A study has been made of the Lingane-Karplus reaction and it was shownthat the titration of manganese at pH 6-7 in pyrophosphate is not affectedby a large number of cations and anions.361 The reaction has also beenused to determine manganese in ferromanganese and other minerals. 362Cobalt, complexed with 1 ,lo-phenanthroline 363 or 2,2’-bi~yridyl,~~~ has beensuccessfully determined with ferric chloride.Formation of the complexconsiderably improves the potential change at the end-point. A titrationof cobalt with molybdicyanide 3e5 gave better results than with ferricyanide.The possibilities of ferricyanide titrations have been reviewed for a numberof metal ions.366Reduction processes include determination of thallium with chromium(I1)ions using conventional arrangement~,~~7 and the use of this titrant fordetermining small amounts of molybdate in the presence of excess of thio-cyanate has been Cerium(m) ions in alkaline solutions haveprovided an accurate method for determining milligram quantities of ferri-cyanide and permanganate with good end-points in 4~-potassium carbonatesolution. Concentrations down to 1.8 x mequiv./l.of ferricyanidegave reliable r e ~ u l t s . 3 ~ ~ Complexing agents have been used in several cases,as in the determination of mercury(I1) with EDTA 370 using a silver amalgamindicator electrode; 200 pg. to 100 mg. of mercury were reliably deter-mined. Calcium and magnesium have been determined in water 371 byautomatic titration with EDTA, the calcium first being titrated in sodiumhydroxide solution in the presence of standard mercuric nitrate solution,and then by adjustment of pH both are determined in the same sample.The formulze of complexes formed by zirconium with EDTA and six othercomplexing agents were investigated and the number of ligands involvedwas determined in each case.372 Formation of the complex KPeMo(CN),357 A.Anton and P. W. Mullen, Talanta, 1961, 8, 817.35sM. J. Kelley, D. J. Fisher, and E. B. Wagner, Analyt. Chem. 1960, 32, 61.359 J. R. Glass and E. J. Moore, Analyt. Chena., 1961, 33, 494.360 J. Beritik, Chem. Zvesti, 1960, 14, 372.361 W. G. Scribner, Analyt. Chem., 1960, 32, 966, 970; W. G. Scribner and R. A.362A. Jellinek and J. HoSala, Hutn. Listy, 1960, 15, 137.363 F. Vydra and R. Pfibil, Talaizta, 1960, 5, 44.364 F. Vydra and R. PFibil, Tulanta, 1961, 8, 824.365 B. Kratochvil and H. Diehl, Talanta, 1960, 3, 346.366 B. R. Sant and S. B. Sant, Z’alanta, 1960, 3, 261.367 R. Majumdar and M. L. Bhatnagar, AnaZyt. Chim. Acta, 1961, 25, 203.368 A. I. Busev and Gyn Li, Vestn.Moskou. Univ., Ser. Khim., 1960, 11, No. 2, 73.369N. H. Furman and A. J. Fenton, Analyt. Chem., 1960, 32, 745.3 7 0 H. Khalifa and M. G. Allam, Analyt. Chim. Acta, 1960, 22, 421.371 J. Haslam, D. C. &I. Squirrell, and I. G. Blackwell, Analyst, 1960, 85, 27.372 B. I. Intorre and A. E. Martell, J . Amer. Chem. SOC., 1960, 82, 358.Anduze, ibid., 1961, 33, 770426 ANALYTICAL CHEMISTRYhas been established by studies of the reaction between iron and molybdi-cyanide ions.373Several papers have been devoted to the determination of halides.Bromides in the range 87-193 pug. have been determined in the presence ofmercuric ions by using an amalgamated silver wire electrode and titrationwith silver nitrate in perchloric acid solution.374 Micro-amounts of iodidein a large excess of chloride were determined by a null-point potentiometricmethod which was claimed to be rapid when applied to iodised salt;3755-100 p.p.m.were determined with an average error of <0.3 p.p.m. byusing a silver-silver iodide electrode. Chlorides are readily determinedpotentiometrically after combustion of organic compounds by the oxygen-flask method.376 A good dead-stop method for the determination ofalkali sulphides involves the use of cadmium acetate. Only hydroxide andcyanide ions interfere in the titration.377 Extreme dilutions (10 - 7 ~ ) arealso claimed by a silver nitrate t i t r a t i ~ n . ~ ~ ~ In a similar investigation,small amounts of sulphide, hydrosulphide, and free hydrogen sulphidewere determined by appropriate adjustments of the pH.379 Borates inmixed fertilisers have been simply determined, after precipitation of thephosphate by bismuth, by a mannitol titration using an identical pH pro-cedure.380 Some inorganic ion8 have been titrated in non-aqueous solvents.Titrations of iodine, bromine, copper(=), iron(m), and antimony(v) havebeen carried out with chromium(=) and titanium(m) chlorides in NN-dimethylformamide.381 Sulphate ions in an acetic acid medium weredetermined by adding excess of barium acetate and back titrating theexcess with perchloric acid in acetic acid.268 The method was applied tothe total sulphate content of solutions used for dissolving reactor fuels.In the organic field, organic solvents are generally used.A comparisonof solvents for non-aqueous titrations of weak organic bases with perchloricacid has shown that acetic acid is preferable to formic or propionic acid inspite of their better levelling 382 Alkoxyl groups have beendetermined by conversion into the alkyl iodide, which was absorbed inpyridine and titrated with tetrabutylammonium hydroxide. 269 The sametitrant and solvent have been used for titrating the 3,5-dinitrobenzoatesof a number of primary and secondary alcohols.383 A number of car-boxylic acid chlorides have been titrated directly in tetrahydrofuran withcyclohexylamine, an ordinary glass-calomel assembly being ~ s e d . 3 ~ ~ Car-373 W. U. Malik and s. I. Ali, Talanta, 1961, 8, 737.374H. J. V. Tyrrell and B.A. Dowson, Analyst, 1960, 85, 528.s7sH. V. Malmstadt and J. D. Winefordner, A d y t . Chim. Acta, 1961, 24, 91.376 J. Haslam, J. B. Hamilton, and D. C. M. Squirrell, Analyst, 1960, 85, 856;J . Appl. Chem., 1960, 10, 97; D. G. Newman and C. Tomlinson, Mikrochim. Ada,1961, 73.377 S. A. Kiss, Talanta, 1961, 8, 726.378 M. W. Tamele, V. C. Irvine, and L. B. Ryland, AnaEyt. Chem., 1960, 32, 1002.37s K. P. Mishchenko, T. A. Tumanova, and I. E. Flis, Zhur. analyt. Khim., 1960,3soH. N. Wilson and G. U. M. Pellegrini, Analyst, 1961, 86, 517.381 J. F. Hinton and H. M. Tomlinson, Anulyt. Chem., 1961, 33, 1502.M. Gutterson and T. S. Ma, Mikrochim. Acta, 1960, 1.3B3 W. T. Robinson, R. H. CundX, A. J. Sensabaugh, and P. C. Markunas, Talanta,15, 211.1960, 3, 307.384L. J. Lohr, Analyt. Chem., 1960, 32, 1166C ART WRIGHT , WE S T W 0 0 D , 427boxylic acids do not interfere, but free hydrochloric acid does, and mustbe corrected for.Differential electrolytic potentiometry, developed by Bishop, has shownpromise of becoming a highly accurate method a t low concentrations. Aspecial study has been made of the oxidation of hydrazine by electrogeneratedbromine down to ~0-6M-so~utions. An accuracy of &0*1% at these levelsis claimed.385 Athorough examination of the variables such as electrode size and position,source, potential, etc., and their effects on the titration curve, has beenmade. An optimum ballast load resistance and controlled cathode currentdensity are required to avoid distortion of the curves.386This is a rapidly expanding technique which hasbeen almost exclusively developed in the United States of America.Rein-muth et al. have studied the theoretical and mathematical aspects of thecurrent-time curves 38 and the significance of the electrode processes.388Theoretical studies of transition times and diffusion at cylindrical electrodeshave been made with a view to checking their analytical pos~ibilities.~~~Errorsarising from oxide film on the platinum cathode were investigated andindirect methods for determining oxalic acid and iron(u1) were devel0ped.3~~Manganese in steels was determined by oxidation at a gold electrode in anacid periodate solution at +O.SO v (S.C.E.).391The reduction of perchlorate to chloride catalysed by molybdenum hasbeen studied and shown to be suitable for analytical purposes.A mechan-ism involving molybdenum-(v) and -(n) has been s~ggested.3~2Studies of oxide films on platinum electrodes have shown that films upto an equivalent of 80 p-coulombslcm. permit normal diffusion control ;reduction of the oxide occurs by a 4-electron pr0cess.3~~ A novel applica-tion involves liquid bismuth used as a coolant in reactor technology. Tracesof zinc are picked up as corrosion products and can be determined by makingthe molten bismuth the anode in a fused lithium chloride-potassium chlorideelectrolyte. moles/ml. can be determined 394High Frequency.-A recent review by Ladd and Lee 395 gives a clearaccount of the theory, the available apparatus, and applications to ionicreactions.Most of the rather small number of papers which have appearedhave been devoted to improvements in instruments or circuits. A newtitrimeter operating at 130 Mc./sec. has been shown to be able to determine385 E. Bishop, Milcrochim. Acta, 1960, 803.887W. H. Reinmuth, Analyt. Chem., 1960, 32, 1509, 1514; 1961, 33, 322; 1961,AN D WIL SO NVolumes down t o 50 pl. are dealt with in a special cell.Chronopotentiometric.Cerium(1v) has been studied over the range 2-20 millimoles/litre.Zinc down to 1.19 xto &4y&E. Bishop, Analyst, 1960, 85, 422.33. 485.~ 3 8 8 A . C. Testa and W. H. Reinmuth, Analyt. Chem., 1961, 33, 1320, 1324; 1960,32. 1518.389D. G. Peters and J. J. Lingane, J . Electroanalyt. Chem., 1961, 2, 249.390D.G. Davis, Analyt. Chem., 1961, 33, 1839.selD. G. Davis and J. Ganchoff, J. Electroanalyt. Chem., 1960, 1, 248.39zG. A. Rechnitz and H. A. Laitinen, Analyt. Chem., 1961, 33, 1473.393 J. J. Lingane, J . Electroanalyt. Chem., 1961, 2, 296.304 J. D. van Norman, Analyt. Chem., 1961, 53, 946.995M. F. C . Ladd and W. H. Lee, Talanta, 1960, 4, 274428 ANALYTICAL CHEMISTRY1 ,ug./ml. of hydrochloric acid and 20 ,ug./ml. of acetic acid by using sodiumand ammonium hydroxides as titrants.396 The feasibility of using a modu-lated off-balance R.F. signal from the detector side of a R.F. impedancebridge was tested and found to give very suitable titration curves at 30Mc./sec. for 0-Oh-hydrochloric and 0-1N-acetic a ~ i d s . 3 ~ ~ A simple H.F.titrator, suitable for a number of student applications and based on a hetero-dyne-beat principle a t 120 Mc./sec., has been described.398 A simpletransmission line operating at 190 Mc./sec.involves changes in grid currentwhich are transformed to a voltage applied to a recorder, and are used indetermining free acid in uranium solutions by alkali titration, and thoriumby oxalic acid or EDTA titration, in mg. quantities.399 The H.F. methodhas been combined with paper chromatography as a zone locator,400 par-ticularly for lithium, sodium, and potassium where the change in impedanceof the cell has been used as a measure of these elements,401 and as a “ humid-ity gauge.” 402Chloride-ion concentrations down to 0.3 p.p.m. and sulphide to 1 p.p.m.have been recorded by H.F.titrimetry using 0.001N-silver nitrate andoperating at 11 M~./sec.~O~Oxalic, malonic, succinic, tartaric, and citric acids have been determinedin mg. quantities by ammonia in the 130 Mc./sec. region by means of theapparatus quoted above. 396 Tervalent arsenic and antimony have similarlybeen determined with iodine.*04A study has been made of various solvents suitable for H.F. titrimetryof weak acids, and acetonitrile was considered to give the best response withtetrabutylammonium hydroxide as titrant. 405 The comparative behaviourof the alkali-metal methoxides in benzene-methanol solution by titrationwith aliphatic and aromatic weak acids in dimethylformamide showed thatthe rubidium and cmium compounds acted as strong bases, but lithiummethoxide was very weak.The ammonium ion acted as a strong acid.4068. Determination of elements in organic compoundsThe development and applications of the microchemical balance havebeen reviewed.407 Some corrections are advocated for achieving the highestaccuracy in microchemical weighings 408 and methods for deriving themare given. ,Two reviews have been published of quantitative organic microanalysis.3*6E, Pungor and L. Balazs, Mikrochim. Acta, 1960, 118.397 J. E. Walker, J. L. Lambert, and L. D. Ellsworth, Analyt. Chem., 1960, 32, 9.398 J. K. Clinkscales and H. Frye, J . Chem. Educ., 1960, 37, 304.399D. L. Manning and 0. Menis, Talanta, 1960, 6, 30.400 G. G. Blake, Analyt. Chim. Acta, 1960, 22, 38.401 J.A. Broomhead and N. A. Gibson, Analyt. Chim. Acta, 1961, 24, 446.4ozG. G. Blake, Analyt. Chim. Acta, 1960, -23, 10.403 N. van Mews, J. Electroanalyt. Chem., 1961, 2, 17.404E. Pungor and L. Balazs, Mikrochim. Acta, 1960, 678.406 E. L. Grove and W. S. Jeffery, Talanta, 1960, 7, 56.406 S. F. Ting, W. S. Jeffery, and E. L. Grove, Talanta, 1960, 3, 240.‘07 G. Ingram, I n d . Chemist, 1961, 37, 343.40a W. Durselen, 2. Chem., 1961, 1, 119CARTWRIGHT, WESTWOOD, AND WILSON 429One 409 deals with weighing and preparing samples, determining carbon,hydrogen, oxygen, and nitrogen, the flask method for a number of elements,and the determination of many functional groups. The other is confinedto quantitative elemental meth0ds,~10 and deals with the importance of theflask-combustion method, with improvements in carbon and hydrogendetermination, and with problems involved in determining traces of elementsand in ultramicro-analysis. In a critical review of the oxygen-flask method,Macdonald 411 discusses procedures for the combustion, and for determininghalogens, sulphur, phosphorus, arsenic, boron, and some metals.Themethod has been modified 412 to deal with the determination of residuesof arsenic, chloride, bromide, manganese, and nickel in plant material, andprocedures have been described 413 for the rapid detection and semiquanti-tative estimation of a number of elements in plastic materials.A modification of furnace design is described 414 which combines rapidheating of the combustion tube with reliability.The process of decomposi-tion of organic compounds in a rapid flow of oxygen has been disc~ssed.~l~Ingram 416 has described an apparatus in whichthe sample is rapidly introduced into a closed heated tube containing oxygen ;when combustion is complete the gases are swept out and the determinationof carbon and hydrogen is completed in the usual way. Determination ofcarbon following flask combustion is described by Cheng and S m ~ l l i n . * ~ ~The sample is ignited electrically, the carbon dioxide is absorbed in alkalinebarium chloride solution, and the separated barium carbonate is dissolvedin standard acid, the excess of which is titrated.Thermally stable samples, enclosed in a platinum roll, have been heatedby an induction furnace,418 enabling a temperature of 1300" to be attainedwithout softening the silica combustion tube.A number of catalysts used in rapid combustion methods have beencompared, and Co304 has been selected as the best.The kinetics andmechanism of the catalysed combustion were examined, and conditions forthe shortest combustion and sweeping times are given.419 The use of Co,O,as catalyst is also reported in a method 420 whereby the sample is burnedin oxygen to give carbon dioxide, in nitrogen to give water which is reducedto hydrogen, or in carbon dioxide to give nitrogen, the gas in each casebeing measured by thermal conductivity. The same catalyst is used ina semimicro-method for carbon and hydrogen. 421 The " decomposed silverpermanganate " catalyst is recommended for organomercury compounds,Carbon and hydrogen.J .40B W.Schoniger and H. Lieb, Purnaco, E d . Sci., 1961, 2, 81.410P. Gouverneur, Chem. Weekblad, 1961, 57, 313.411 A. M. G. Macdonald, Analyst, 1961, 86, 3.412 W. H. Gufenmann, L. E. Saint John, D. L. Barry, E. D. Jones, and D. J. Lisk,Agric. Food Chem., 1961, 9, 50.413 J. Haslam, 5. B. Hamilton, and D. C. M. Squirrell, Analyst, 1961, 86, 239.414 J. A. Kuck, J. W. Berry, and L. H. Barnum, Microchem. J., 1961, 5, 193.415V. A. Klimova and T. A. Antipova, Zhur. analit. Khim., 1961, 16, 343.416 G. Ingram, Analyst, 1961, 86, 411.417 F. W. Cheng and C. F. Smullin, Microchem. J., 1961, 5, 43.41sD. E. Butterworth, Analyst, 1961, 86, 357.41eM. VeEeFa, D. Snobl, and L.Synek, Mikrochim. Acta, 1961, 370.llaoM. VeEeFa, Talanta, 1961, 8, 446.421C. Meyer and G. Vetter, Chem. Tech. (Berlin), 1961, 13, 104430 ANALYTICAL CHEMISTRYand a method is given 422 for determining mercury, if halogens are absent,as well as carbon and hydrogen.Although the method was not tested on fluorocarbons, difficulties dueto fluorine in other compounds were overcome by using magnesium oxidein a silver gauze roll, the combination proving effective in removing all thehalogens and The method of halogen and sulphur determinationhas been modified 424 to permit simultaneous determination of carbon andhydrogen. The preparation is described 425 of silver in granular form, whichhas the same capacity for removing halogens and sulphur as silver wool,but is more convenient to use.Carbon- 14 can be determined after oxygen-flask combustion by propor-tional counting 426 or, as well as tritium, by liquid-scintillation techniq~es.~27Nitrogen. A convenient apparatus is described 428 for generating carbondioxide for Dumas combustion, using potassium hydrogen carbonate andsulphuric acid.An investigation 429 of the Dumas combustion by gaschromatography has resulted in recommendations for both apparatus andmethod. The combination of combustion and gas chromatography hasbeen used 430 to determine nitrogen, in one method in terms of carbon : nitro-gen ratio, and in another, using carbon dioxide as the carrier gas, by thenitrogen peak alone; neither method requires a weighed sample, and goodaccuracy is claimed for both.Methods for determining nitrogen in compounds containing fluorine havebeen reviewed, and a modified Dumas train has been devised 431 in whichhigher temperatures are used and a simple generator permits intermit tentflow of oxygen when required.Comparison has been made of Dumas, Kjeldahl, and other methods ofdetermining nitrogen in solid fuels, 432 the recommended method beingreductive digestion with metallic lithium, followed by decomposition of thenitride with phosphoric acid and distillation of ammonia from the alkalinesolution.The determination of nitrogen, following combustion, by measure-ment of thermal conductivity has already been mentioned. 420The process of digestion in the Kjeldahl method has been investigated byBaker,*33 and clear evidence is advanced that mercuric oxide, of 21 singleand mixed catalysts examined, is the most effective; a higher than usualconcentration of potassium sulphate is also recommended. A bent test-tube has proved more reliable 434 than the conventional Kjeldahl flask inthe digestion of blood plasma and plant material.422A.I. Lebedeva and E. F. Fedorova, Zhur. analit. Khim., 1961, 16, 87.423G. Ingram, Analyst, 1961, 86, 539.424 Toshihiro Onoe, Chizuru Furukawa, and Hiro Otsuka, Ann. Report Takamine425 Tetsuo Mitsui, Osamu Yamamoto, and Keikichi Yoshikawa, Mikrochim. Acta,426H. Kienitz and 0. Riedel, 2. unalyt. Chem., 1961, 179, 93.4 2 7 R . G. Kelly, E. A. Pests, and D. A. Buyske, Analyt. Bwchem., 1961, 2, 267.428 M.Hocheneggar, Mikrochim. Acta, 1961, 431.429 M. &mek and K. TesaFik, Coll. Czech. Chem. Comm., 1961, 26, 1337.43oR. H. Reitsema and N. L. Allphin, AnaEyt. Chem., 1961, 33, 355.43lG. Kakabadse and B. Manohin, Analyst, 1961, 86, 512.432 W. Radmacher and A. Hoverath, L;rliickazcf, 1960, 96, 1146.433 P. R. W. Baker, Talunta, 1961, 8, 57.434V. Fojtova and J. Pud, Chem. Listy, 1961, 56, 201.Lab., 1959, 11, 100,1961, 521CARTWRIGHT, WESTWOOD, AND WILSON 43 1The direct determination of oxygen by the Unterzauchermethod has been applied to organic oxygen in coals,435 and a new method 436employing platinised asbestos and platinum-rhodium gauze a t 700" hasbeen applied to compounds containing carbon, hydrogen, and oxygen ; thecarbon dioxide and water produced by pyrolysis are absorbed in one pairof absorption tubes, and the carbon monoxide and hydrogen are oxidisedby heated copper oxide and absorbed in another pair of tubes, the first ofwhich is weighed.Accuracy of better than &-0-2y0 was obtained for mostsamples.Halogens. Some aspects of halogen determination have already beenm e n t i ~ n e d . ~ l ~ - ~ l ~ ? 424 Although most workers now use the oxygen-flaskmethod of decomposition for halogens, with a variety of finishes, combustionin a stream of oxygen has received attention. Fildes and Macdonald 437describe titrimetric methods for determining individual halogens in presenceand absence of nitrogen and sulphur, following a specified rapid combustionprocedure, and Belcher and Fildes 438 deal with simultaneous determinationof chlorine, bromine, and iodine in presence of nitrogen and sulphur, witha study of optimum conditions for absorption.Pella 439 makes provisionfor dealing with explosive and volatile compounds, and gives methods withtitrimetric finishes for determining chlorine, bromine, and sulphur separately,and chlorine and sulphur simultaneously. A modified combustion overplatinum contacts, with the products drawn into an evacuated flask con-taining hydrogen peroxide solution and titrated amperometrically, hasbeen used 440 in a general method of determining chlorine, bromine, andiodine. The determination of iodine after combustion in the oxy-hydrogenfla,me is des~ribed.~~IIn the oxygen-flask combustion of compounds with high halogen contentit is recommended 442 that the filter paper be saturated with dilute potassiumnitrate solution.Following flask combustion, the titrimetric determinationusing mercuric nitrate with diphenylcarbazone as indicator is generallyfavoured,442, 4439 444 but Hennart 445 proposes a method involving additionof excess of silver nitrate, filtering off the resulting precipitate, treating thefiltrate with excess of K,[Ni(CN),], and titrating with EDTA the nickeldisplaced by silver from the cyanide complex.Olson andShaw 446 use the spectrophotometric finish with thorium chloranilate.Martin et advocate the thorium nitrate titration with Alizarin S asindicator for major quantities, and the colorimetric zirconium-alizarinOxygen.Various methods are still favoured for determining fluorine.435 A.Crawford, M. Glover, and J. H. Wood, Mikrochim. Acta, 1961, 46.436V. S. Pansare and V. N. Mulay, Mikrochim. Acta, 1961, 606.437 J. E. Fildes and A. M. G. Macdonald, AnuZyt. Chim. A&, 1961, 24, 121.438R. Belcher and J. E. Fildes, Artalyt. Chim. A d a , 1961, 25, 34.43gE. Pella, Mikrochirn. Acta, 1961, 472.440 S. Greedeld, R. A. D. Smith, and I. L. Jones, Mikrochim. Acta, 1961, 420.441 F. Ehrenberger, Mikrochim. Acta, 1961, 590.lrpaI. A. Favorskaya and V. I. Lukina, Vestnilc Leningrad Univ., 1961, 2, 148.443 W. A. Cook, Microchem. J., 1961, 5, 67.444 D. C. White, Mikrochim. Acta, 1961, 449.445 C. Hennart, Mikrochim. Acta, 1961, 543.44eE. C. Olson and S .R. Shaw, Microchem. J . , 1961, 5, 101.447 F. Martin, A. Floret, and M. Dillier, Bull. SOC. chim. France, 1961, 460.432 ANALYTICAL CHEMISTRYmethod for traces. Johnson and Leonard 448 apply a spectrophotometricmeasurement to the blue complex formed by fluoride ions and the cerium(m)chelate of alizarin complexan, pointing out that the use of borosilicate glassflasks tends to give low results; the blue complex has been investigated inanother context. 449 Nuclear magnetic measurement 450 provides a specificand rapid method of determining fluorine in fluorocarbon liquids, but notwith the accuracy usually sought. Valach451 has critically examined anumber of methods of determining fluorine.Decomposition of organic compounds by the biphenyl-sodium dimethoxy-ethane complex, for determination of halogens, has been modified to dealwith volatile ~amples.~~2Sulphur. Flask combustion is now generally accepted as the methodof de~omposition.~l~s 453 A 2-litre flask is ~ s e d , ~ ~ 4 with turbidimetricmeasurement of barium sulphate, in determining traces of sulphur inpoly(methy1 methacrylate). Dixon 291 discusses a number of rapid micro-methods, using mainly a conductometric titration with barium ions.Thebarium nitrate titration has been used with Alizarin S 455 and with carboxy-arsenazo-indicators. 456Other elements. Methods have been given for determining phos-phoru~,411~ 457 arsenic, and boron, and metals 4119 412 following the flask' combustion. Boron, with mannitol added, has been titrated potentiometric-ally following Carius oxidation.458 A rapid method for determiningsilicon 459 is based on oxidation of the sample by chromic and sulphuricacids, fltration of the silica and solution of it in sodium hydroxide, followedby addition of ammonium fluoride to convert it into fluorosilicate in thepresence of an acid, and back-titration of the excess of acid with alkali.9.Spectroscopic analysisThis section is again divided into emission spectroscopy, including flamephotometry, fluorimetry, and X-ray methods ; and absorption spectroscopywhich embraces ultraviolet and visual absorption, turbidimetric, atomicabsorption, infrared absorption, and nuclear magnetic resonance methods.General.-In the Proceedings of the 8th Spectrochemical Conference 460papers are included dealing with modern electrical equipment for spectro-chemistry, the determination of several elements by spectrographic methods,and the applications of fluorimetric, X-ray fluorescent, and flame-photometricmethods.a4*C.A. Johnson and M. A. Leonard, Analyst, 1961, 86, 101.449 P. G. Jeffery and D. Williams, Analyst, 1961, 86, 590.a50H. Rubin and R. E. Swarbrick, Analyt. Chem., 1961, 33, 217.451R. Valach, Talanta, 1961, 8, 629.45aR. D. Chambers, W. K. R. Musgrave, and J. Savory, Analyst, 1961, 86, 356.453 C. Vickers and J. V. Willtinson, J . Pharm. Pharmacol., 1961, 13, 72.454 J. Haslam and D. C. M. Squirrell, J . Appl. Chem., 1961, 11, 244.455A. I. Lebedeva and I. V. Novozhilova, Zhur. analit. Khim., 1961, 16, 223.a5eK.F. Novikova, N. N. Basargin, and M. F. Ts9ganova, Zhur. analit. Khwn.,457A. M. Ryadnina, Zavodskaya Lab., 1961, 27, 405.458 D. G. Shaheen and R. S. Braman, Analyt. Chem., 1961, 33, 893.459A. P. Terent'ev, S. V. Syavtsillo, and B. M. Luskina, Zhur. analit. Khim., 1961,1961, 16, 348.16, 83. 480 S. Martino di Castrozza, Metallurg. Ital., 1961, 53, No. 5CARTWRIGHT, WESTWOOD, A N D WILSON 433In a critical review of colorimetric and spectrographic methods for theanalysis of gold, in which the limitations of many methods are discussed,Beamish 461 finds that no colorimetric or spectrographic method yet pub-lished gives the precision of the classical methods.Emission Spectroscopy.-Ignited arc sources have been compared withparticular reference to the determination of boron in steel and of tin andantimony in lead alloy.462 The theoretical and experimental aspects ofthe analysis of gases and vapours by emission spectroscopy have beendiscussed 463 and current literature on molecular emission spectroscopy hasbeen reviewed.Among the many applications of emission spectroscopy to the analysisof metals, the determination of beryllium metal and compounds has beendescribed 464 and a method has been given for the quantitative determina-tion of gallium in mi~ro-samples.~~~Methods for the analysis of non-metals include the determination ofboron in nuclear g r a ~ h i t e , 4 ~ ~ traces of boron in silicon tetrachloride, 467 andthe determination of halogens in solution. 468Further work on the determination of nitrogen in steels 469 has shownthat the Ar 8179 A band, which has been previously used, is a Rowlandghost of the strong Ar band a t 8115.3 A and that it is peculiar to theparticular grating used.is said t o beof more general use.Spectrographic methods continue to find use in the determination oftrace impurities following concentration. Thus copper, zinc, manganese,lead, tin, nickel, and iron in sodium and potassium salts may be determinedfollowing precipitation with 8-hydroxyquinoline and thionalide after theaddition of alumini~m.~70 Traces of cobalt, chromium, copper, man-ganese, molybdenum, nickel, titanium, vanadium, tungsten, zirconium,aluminium, and cadmium in steel can be determined after concentrationwith suitable organic reagents.471The experimental principles and the applications offlame photometry to the determination of various metals have been re-viewed.472 The factors influencing the accuracy of determinations by flamephotometry have been investigatedY4T3 and a study has been made of thefactors iduencing sample flow rate.474In the determination of lithium in silicate minerals it has been foundaslF.E. Beamish, Analyt. Chenl., 1961, 33, 1059.4saT. P. Schreiber and B. W. Joseph, Appl. Spectroscopy, 1961, 15, 8.463 W. D. McGrath, R. J. Magee, W. F. Pickering, and C. L. Wilson, Talanta, 1961,464M. A. Lund and D. L. G. Smith, A.E.R.E. Report-AM 73, 1961.4s5E. M. Murt and J. C . Bready, Appl. Spectroscopy, 1961, 15, 1.rs6F. Gianni and F. Potenza, Analyt.Chisn. Acta, 1961, 25, 90.467T. J. Veleker and E. J. Mehalchick, Analyt. Chem., 1961, 33, 767.468 J. Fijalkowski and A. Zelle, Chem. Analit., 1961, 6, 323.469Hitoshi Karnada and V. A. Fassel, Spectrochim. Acta, 1961, 17, 121.470R. L. Dehm, W. G. Dunn, and E. R. Loder, Analyt. Chem., 1961, 33, 607.471 F. Burriel-Marti, J. Ramirez-Muiioz, and M. del Carmen Asuncih, Inst. Hierro472 W. Leithe, Angew. Chern., 1961, 73, 488.473 S . Dobos and.F. Till, Magyar Kim. Folydirut, 1961, 67, 183.474 J. D. Winefordner and H. W. Latz, Analyt. Chem., 1961, 33, 1727.The line pair N 8216 A-Ar 8053Phme photometry.8, 892.Acero, 1961, 14, 518434 ANALYTICAL CHEMISTRYthat the most accurate results are obtained when interfering elements suchas iron, manganese, and aluminium are removed.475 Sodium and potassiumhave been determined in the presence of other metals,476 and methods havebeen given for overcoming some interferences ; calcium, strontium, andcerium may be suppressed by the addition of aluminium nitrate, whilemanganese, nickel, cobalt, chromium(m), and iron may be retained as theirEDTA complexes on ion-exchange columns.A detailed study has been made of the flame-photometric determinationof silver, and the behaviour of metals and anions associated with silver hasbeen examined.477 Indium and thallium have been determined in anacetylene-air flame, and gallium, indium, and thallium in an oxy-hydrogenflame.478FZzwrimetry. The importance of compiling data of fluorescence sensi-tivities in such a way that the values are independent of the instrumentsused to measure them has been discussed by Parker.479 The conditionsunder which fluorescence is obtained and the presentation of measuredfluorescence spectra have been reviewed.48 OThe use of quinine sulphate as a fluorescence standard has been studied,and measurements have been made of the intensity of its fluorescence inaqueous and acetic acid solutions with additions of sulphuric and perchloricacids.481 I n aqueous solution constant fluorescence intensity can only beobtained at a pH not greater than 2. The intensity is not affected byphosphate buffers but is slightly quenched by phthalate buffers. Whenglacial acetic acid is used as the solvent the fluorescence intensity is greaterand remains constant over the range 0.Ol-l.ON-perchloric acid.Theeffect of chloride ion on the fluorescence of quinine and its dependence onacid concentration 482 and salt concentration 483 have also been studied.The design and circuit details have been given of an improved fluorimeterfor uranium analysis. 484 A simple fluorimeter which has been constructedin the laboratory has been described 485 and an account has been given ofits use in an investigation of the benzoin method for the determination ofboron.In inorganic analysis beryllium has been determined in boron 486 by afluorimetric method using 3-hydroxy-2-naphthoic acid a t pH greater than2.5. Zinc can be effectively determined with Rhodamine B (C.I. BasicViolet 10) by measuring the extinction of the fluorescent solution,487 andRhodamine B has also been used for the determination of gallium in475 J.Liebig and H. Bredehorst, Analyt. Chim. Acta, 1961, 24, 573.476R. N. P. Farrow and A. G. Hill, Talanta, 1961, 8, 116.477 J. A. Dean and C. B. Stubblefield, Analyt. Chem., 1961, 33, 382.478J. Malinowski, D. Dancewicz, and S. Szymczak, Chem. Analit., 1961, 6, 183.479 C. A. Parker, Photoelect. Spectr. Gr. Bull., 1961, 334.48oE. J. Bowen, Photoelect. Spectr. Gr. Bull., 1961, 331.481 J. Eisenbrand, 2. analyt. Chem., 1961, 179, 170.482 J. Eisenbrand and M. Raisch, 2. analyt. Chem., 1961, 179, 352.488 J. Eisenbrand and M. Raisch, 2. analyt. Chem., 1961, 179, 406.484E. N. Haran, J . Sci. Instr., 1961, 38, 273.4 8 5 G .Elliot and J. R. Radley, Analyst, 1961, 86, 62.48sA. I. Cherkesov and T. S. Zhigalkina, Zavodskaya Lab., 1961, 27, 658.487A. K. Babko and Z . I. Chalaya, Zhur. analit. Khim., 1961, 16, 268.4 8 a G . I. Kuchmistaya, Znvodskaya Lab., 1961, 27, 377CARTWRIGHT, WESTWOOD, AND WILSON 435A study has been made of the reaction of selenous acid with 3,3’-diamino-benzidine, which has been adopted for the fluorimetric determination ofsub-microgram amounts of selenium in arsenic. 489The separation and determination of sub-microgram amounts of uraniumin milligram amounts of iron, aluminium, and plutonium has been ~tudied.~~OIn organic analysis fluorimetric methods have been used for the deter-mination of polycyclic aromatic hydrocarbons.491X-Ray methods.The application of X-ray spectroscopy to industry hasbeen described in the Proceedings of an International Conference a t Liege.492Papers presented deal with sample preparation, development of new instru-ments, and applications to numerous determinations, and cover the fields ofX-ray fluorescence, X-ray absorption, and X-ray emission methods.Errors due to sampling in the X-ray fluorescent determination of tita-nium in high-temperature alloy have been inve~tigated~~~3 and X-rayspectroscopy has been applied to the determination of minor constituentsin low-alloy ~tee1.~94Several papers have described the use of X-ray methods in the analysisof elements in petroleum oils. For instance, nickel has been directly deter-mined at a level of 0.1 p .~ . m . ~ ~ ~ and both nickel and vanadium have beendetermined by using added cobalt as an internal standard;496 the methodis said to be especially valuable below concentrations of 2 p.p.m. Sulphurin gasoline oils has been determined by X-ray emission spectroscopy 497in concentrations lower than 0.002%.Absorption Spectroscopy.-Attention is first given to absorption by solu-tions in the ultraviolet and the visible region, and turbidimetry, followedby atomic absorption, infrared absorption, and finally nuclear magneticresonance methods.An enormous volume of work hasagain been published in the field of ultraviolet and visible absorption; onlya few of the papers of more general interest can be included.The pressed disc technique has been found to be useful in the ultravioletregion for samples for which suitable solvents are not available.498 Potas-sium chloride is said to be the most suitable material.The use of ultraviolet spectrophotometry in the evaluation of pharma-ceutically active compounds has been described, and papers published upto October, 1960, have been reviewed.499An investigation has been made of the use of Arsenazo I11 (l&dihydroxy-naphthalene-3,6-disulphonic acid -+ 2,7-bis[ (azo-2)-phenylarsonic acid]) inphotometric analysis.500 The reagent gives colour reactions with a numberUltraviolet and visible absorption.aaeC. A. Parker and L. G. Harvey, Analyst, 1961, 86, 54.4*0 D. G. Boase and J. K. Foreman, Talanta, 1961, 8, 187.lS1 J. H. Chaudet and W.I. Kaye, Analyt. Chem., 1961, 33, 113.4s2 Rev. Univ. Min., 1961, 17, 143.aa3R. F. Stoops and K. H. McKee, Analyt. Chem., 1961, 33, 589.R. E. Michaelis, R. Alvarez, and B. A. Kilday, J . Res. Nat. Bur. Stand., C, 1961,4s6 J. E. Shott, jr., T. J. Garland, and R. 0. Clark, Analyt. Chem., 1961, 33, 506.4e7R. A. Jones, Analyt. Chem., 1961, 33, 71.498 V. A. Shlyapochnikov and V. I. Slovetskii, Optics and Spectroscopy, 1961, 10, 132.4ss J. KritEmar, Pharmazie, 1961, 16, 341.6oo S. B. Savvin, Talanta, 1961, 8, 673.65, 71. 4s5 C. C. Hale and W. H. King, jun., Analyt. Chem., 1961, 33, 74436 ANALYTICAL CHEMISTRYof elements and can be used for the determination of thorium, zirconium,hafnium, uranium, and rare earths, being most selective for thorium,zirconium, and uranium(1v).An investigation has been made of the stability of the curcumin complexused for the determination of b0ron.~O1 Studies were carried out withthe dry complex, and with ethanolic solutions of the complex stored both a t0" and at room temperature.The colorimetric analysis of silica by means of the yellow molybdosilicatecomplex has been critically reviewed,502 and a rapid procedure for thedetermination of total and soluble silica has been given based on studiesof a number of factors affecting the reaction.A comparison has been made of different reducing agents in the deter-mination of phosphorus by the formation of heteropoly- blue.503 Consid-eration is given to the effect of heat, of addition sequence and the choiceof instrument, and of reducing solutions.It has been shown that it isnecessary to strike a balance between the stability of the colour with timeand the magnitude of the extinction coefficient of the heteropoly-blue;established methods must be closely followed since the stability of colourintensity is easily lost. The optimum conditions for the development ofcolour have also been studied in the colorimetric determination of phos-phorus, arsenic, germanium, and sili~on.~O~ It has been shown that theintensity of colour is greatly influenced by the concentrations of bothmolybdate and hydrogen ions.A new colorimetric reagent, Solochrome Violet R.S. (C.I. MordantViolet 5), has been proposed for the micro-determination of molybdenum.505Copper, iron, bismuth, zirconium, cerium, tungsten, and vanadium interferewhen present in ten-fold excess.Belcher and West 506 have studied the cerium( m)-alizarin coniplexan-fluoride reaction and have found that a t an optimum pH range of 5-0-5.2the method may be applied over a wide range of fiuoride-ion concentration.From a study of the interference of 23 selected cations and three anions itwas concluded that practically all serious cationic interference could beovercome by masking agents.I n the case of aluminium, iron(m), chrom-ium(m), and vanadium( v) preliminary extraction with 8-hydroxyquinolinewas necessary, while calcium and beryllium were removed by 8- hydroxy-quinoline and chloroform. The same authors have made a comparativestudy of some lanthanon chelates of alizarin complexan as reagents forfluoride.The lanthanum reagent in aqueous solution a t pH 5.2 was foundto be the most sensitive.Nickel can be determined as the stable brown complex with formald-oxime 508 and the method is said to be slightly more sensitive than thatusing dimethylglyoxime.501 D. E. Williams and J. Vlamis, Analyt. Chem., 1961, 33, 1098.602G. J. S. Govett, Analyt. Chim. Acta, 1961, 25, 69.603R. P. A. Sims, Analyst, 1961, 86, 584.504Teru Yuasa, Reports Govt. Chem. In&. Res. Inst., Tokyo, 1961, 56, 43.606H. Khalifa and S. W. Bishara, 2. analyt. Chem., 1961, 182, 96.50'3R. Belcher and T. S. West, Talanta, 1961, 8, 853.507 R. Belcher and T. S. West, Talanta, 1961, 8, 863.508 Z. Marczenko and K. Kasiura, Chem.Analit., 1961, 6, 353CARTWRIGHT, WESTWOOD, AND WILSON 437A colorimetric method for the determination of microgram quantitiesof water has been described, based on the change in extinction when theKarl Fischer reagent reacts with water.509In the organic field the absorption spectra of acetone and diacetonealcohol have been determined in ethanol,510 and a method for their deter-mination when admixed has been described.Only a small number of papers have appeared on thissubject and it is apparent that analysts in general prefer more direct andreproducible methods where possible. The method, however, has beenreviewed by Peaker 511 particularly for the characterisation of polymers.By using a Spekker absorptiometer the applicability of the process has beenstudied for polystyrene and Perspex.What is termed an " absolutemethod " has been claimed and is based on the measurement of the turbidityat a wavelength for a system where the turbidity is proportional to thereciprocal of .the wavelength. Application to the case of silver bromidesols is claimed to give reasonably good results.512The determination of traces of sulphur below 300 p.p.m. in leaded gaso-line can be carried out by modifying the A.S.T.M. lamp-turbidimetricmethod. In the subsequent determination of the sulphate as bariumsulphate accuracy of under 5% is claimed down to as low as 30 p.p.m.513Elemental sulphur in soils can be analysed consistently in the range 1-7,ug./ml. by an extractive process with acetone and direct measurement at420 mp.Results on a variety of soils agreed with those obtained by otherand longer methods.514In the organic field, hydrazine has been determined down to l O - 4 ~ byoxidation with selenium dioxide in acid solution whereby a selenium sus-pension is produced. Organic sfiabilisers, however, are necessary, and timeof standing, acidity, etc., are all important. An accuracy of about 5%is claimed. 515Traces of water in hydrocarbons have been determined by the turbidityproduced by TiCl, vapour. It is claimed that lo-,% water can be rapidlydetermined by using a calibration curve.518 Cholesterol has been quanti-tatively determined in blood serum by direct addition of sodium ethoxide.A linear relationship holds between the turbidity and the cholesterol con-centration under the conditions given ; results were obtained which wereconsistent with those from longer and less simple meth0ds.~17Recent advances in atomic absorptionspectroscopy have been reviewed and controllable variables and featuresof equipment have been discussed.Atomic absorption methods have been applied to the determination of50s D.A. Otterson, Analyt. Chem., 1961, 33, 450.510A. Basiriski and A. Narebska, Roczniki Chem., 1961, 35, 1131.sllF. W. Peaker, Analyst, 1960, 85, 235.slaE. J. Meehan and W. H. Beattie, Analyt. Chem., 1961, 33, 632.61sR. W. Klipp, Analyt. Chem., 1961, 33, 1912.514 M. G. R. Hart, Analyst, 1961, 86, 472.s15M. R. F. Ashworth, Mikrochim. Acta, 1961, 5 .616 M. Kubinov&, 0.Vilim, and V. Svoboda, Coll. Czech. Chem. Comrn., 1961,26, 1320.s17 G . R. Kingsley and 0. Robnett, Analyt. Chem., 1961, 33, 561.618 J. W. Robinson, Analyt. Chem., 1961, 33, 1067.Turbidimetric.Atomic absorption spectroscopy.438 A N AL Y TI C AL C HE MIST R Ymetals in a wide range of materials ; for example, methods have been describedfor the determination of magnesium in biological materialsY519 zinc in agricul-tural materials,520 lead in ~ r i n e , ~ ~ l and lead in gasoline.522An investigation has been made of the factors affecting the determinationof molybdenum, and the apparatus used has been described.523 I n reducingflames, calcium, strontium, manganese, iron, and sulphate ions in solutioncause different degrees of depression in molybdenum absorption, but all inter-ferences were suppressed by the addition of excess of aluminium chloride.The use of the technique of pressed samples ininfrared spectroscopy has been reviewed.524 A study of the use of alkalihalide discs 525 has shown cases of anomalous behaviour. With benzoic,succinic, and adipic acids and succinimide in potassium bromide and potas-sium chloride discs the anomalies are due to adsorption of the sample on tothe surface of the alkali halide particles.The anomalous behaviour ofl-naphthylacetamide is caused by polymorphism of this substance, whilethe behaviour of succinimide in potassium iodide discs is due to the forma-tion of an addition product.A microtechnique for the study of solids has been described whichpermits sample weights as low as 4 fig.to be cells are constructedhaving windows of diamond or sapphire enabling spectra to be obtained inthe 2-35 micron region.The general application of infrared spectrometry to inorganic substanceshas been reviewed,527 and a comprehensive account has been given of theuse of infrared spectroscopy in the paint field.528 A study has been madeof the reproducibility of infrared band intensities, 529 and suggestions havebeen made for the correlation of results obtained from different instruments.Among particular applications of infrared spectroscopy a study has beenmade of the simultaneous determination of sulphate, nitrate, and nitritein water samples. 530 Dilute samples are concentrated and the interferenceof phosphate ions, carbonate ions, and organic material is suppressed byanion exchange.Water in ethanol has been determined by two methodsJ531 one involvingdilution of carbon tetrachloride for water contents of 0 to 9%, and a directmethod for water contents of 0 to 2%.Water has also been determined byreaction with 2,Z-dimethoxypropane in the presence of methanesulphonicacid catalyst to form acetone, which is then measured.532 Carbonyl com-pounds, basic substances, and salts of weak acids and strong bases interfere.Infrared absorption.519 J. B. Dawson and F. W. Heaton, Biochem. J., 1961, 80, 99.520 J. E. Allan, AnaEyst, 1961, 86, 530.521 J. B. Willis, Nature, 1961, 191, 381.522 J. W. Robinson, Analyt. Chim. Acta, 1961, 24, 451.523D. J. David, Analyst, 1961, 86, 730.524A.A. Boldin and R. F. Vasil'ev, Zauodslcaya Lab., 1961, 27, 819.525A. Tolk, Spectrochim. Acta, 1961, 17, 511.526E. R. Lippincott, F. E. Welsh, and C. E. Weir, AnaEyt. Chem., 1961, 33, 137.527V. V. Klimov. Zavodskaya Lab., 1961, 27, 292.628 Off. Dig. Fed. SOC. Paint !kchnol., 1961, 33.629H. A. Szymanski and D. W. Teloh, Analyt. Chena., 1961, 33, 814.530 I. Citron, Han Tai, R. A. Day, jun., and A. L. Underwood, Talanta, 1961,8,798.S S l P . Ferrer Pi and L. Condal-Bosch, Ajinidud, 1960, 17, 280.532F. E. Critchfield and E. T. Bishop, Analyt. C'hem., 1961, 33, 1034CARTWRIGHT, WESTWOOD, A N D WILSON 439A method has been described for the simultaneous determination ofmethoxy- and ethoxy-gro~ps.~~~ The method is accurate and rapid andis superior to previous methods in that only small samples are required,scrubbing is eliminated, and no interference is caused by sulphur in anyform or in any amount.The use of nuclear magnetic resonancemethods in organic analysis has been reviewed 534 and a guide is given tothe interpretation of the nuclear magnetic spectrum of a single compound.The rapid determination of fluorine in single compounds and mixtureshas been de~cribed.~~o A measuring time of one minute enables the fluorinecontent of a 20 ml. sample to be measured with a relative error of 1% anda detection limit of about 12 mg.of fluorine. With 0.2 ml. samples therelative error is increased to 2% with a detection limit of 3 mg. of fluorine.Nuclear magnetic resonance.10. Electrical methodsUnder this heading are grouped electrodeposition, polarography, radio-chemistry, and mass spectrometry.Polarography accounts for the greatestvolume of published work and this grows yearly. Some idea of the proli-feration of work on this subject can be gleaned from the review by Wawzo-nek 535 which quotes 710 papers on organic polarography alone during theperiod 1958-1960; many of these directly or indirectly have analyticalsignificance. In view of their probable importance a short sub-section onthe newer techniques such as a.c., cathode ray, and allied methods has beenincluded. Owing to their greater sensitivity and resolution and the avail-ability of appropriate instruments they are gaining ground. Since theyhave extended the limits of determination from the 1 0 - 5 ~ region of classicalpolarography to 10-7-10-s~, they are well suited to the examination ofhighly purified materials, as required by some of the newer technologies.Here alsoonly direct analytical applications have been considered.Much has beenpublished in non-analytical journals and may escape notice. Radioactiva-tion techniques have increased and some elegant procedures for trace elementsare reported.Mass spectrometryhas been used in combination with radiochemistry to determine traces, andwith gas chromatography to determine the components of complex mixtureswith success.Electrodeposition, however, is generally on the decline and has largelybeen replaced by other more rapid, more sensitive, and more elegantmethods.Electrodeposition.-Little new work has appeared on this technique inthe last two years.A review of electroanalysis has foreshadowed thecontinual decline of this method in favour of the more convenient coulo-metric methods.536Radiochemical applications are legion and are increasing.There have been several combinations of technique.633 D. M. W. Anderson and J. L. Duncan, Tulunta, 1961, 8, 1.684 J. C. Martin, J . Chem. Educ., 1961, 38, 286.636 S . Wawzonek, Analyt. Chem., 1960, 32, 1 4 4 ~ .636D. D. De Ford, Analyt. Chern., 1960, 32, 3 1 ~ 440 ANALYTICAL CHEMISTRYCopper has been determined in lead-base and tin-base alloys by con-trolled potential methods in amounts as low as 0.2yo in an acid solutioncontaining tartaric acid. Antimony under 1.5% does not interfere.Silverand bismuth codeposit, and procedures are given for dealing with them.537Lead and tin have been determined in lead-tin solders; 538 the lead isdeposited at pH 7-86 with a change in pH near the end-point t o 4-8-53by addition of hydrochloric acid. Hydrazine is added to avoid depositionof lead dioxide on the anode. Tin is then deposited by making the solutionstrongly acid and increasing the deposition voltage; the methods have beensuccessfully applied to N.B.S. solder 127A and B.C.S. white metal 177.Developments of these methods have enabled consecutive determinationsof copper, antimony, lead, and tin in lead-base 539 and tin-base 540 alloysto be made. Mercury has been determined to &lyo in mercurial andorgano-mercurial pesticides by deposition at a silver-plated platinum-gauzecathode.541 A composite procedure for the analysis of aluminium bronzesutilises the deposition of copper from an ammonium nitrate solution, thoughother metals are determined by other meth0ds.~~2 The separation ofpraseodymium and neodymium under a variety of conditions has beeninvestigated in a lithium citrate electrolyte.543Applications have been made to the separation and determination ofradioactive elements in EDTA solution. Lead-210 and bismuth-210 havebeen deposited from extremely dilute solutions on a nickel cathode at pH 3.5in nitric acid, counting methods being used to determine the yield. Polo-nium was best isolated by internal electrolysis using a silver electrode. In5 ml.1 mc. of Po was recovered with an efficiency of 98%.544 Electrolyticseparations of trace amounts of uranium, neptunium, plutonium, andamericium have been studied in a variety of acidic electrolytes and a simpleprocedure for isolating plutonium from the other elements is described; itis deposited directly at high current density after addition of oxalic acidto prevent interference from iron.545Polarograpb.-This technique continues to grow in popularity andaccounts for more publications than any other direct electrochemical methodof analysis. In a report such as this, a comprehensive assessment is impos-sible and only a selection of applications of possible interest to analystscan be made.Recent general reviews have discussed methods and instru-mentation.546 Special reviews have appeared on organic onindustrial uses, 547 and on applications to food analysis.548 Several theo-retical papers have appeared which discuss diffusion processes at the drop-537 B. Alfonsi, Analyt. Chim. Acta, 1960, 22, 431.53aB. Alfonsi, Analyt. Chirm. Acta, 1960, 23, 375.639 B. Alfonsi, Analyt. Chim. Acta, 1961, 25, 274.640 B. Alfonsi, Analyt. Chim. Acta, 1961, 25, 374.641F. Vernon, Analyt. Chem., 1961, 33, 1435.542 M. Freegarde and B. Allen, Analyst, 1960, 85, 731.643E. I. Onstott, Analyt. Chem., 1961, 33, 1470.s44V. Verbersik, 2. analyt. Chem., 1960, 175, 405.645 A. G. Samartseva, Atomnaya Energiya, 1960, 8, 324.646 D. N. H u e , Analyt. Chem., 1960,32,137~; H.W. Niirnberg and M. von Stackel-647 W. Biichler, 2. analyt. Chem., 1960, 173, 17.648 H. Woggon, Ernuhrungsforschung, 1960, 5, 119.berg, J . Electroanalyt. Chem., 1961, 2, 181, 350CARTWRIGHT, WESTWO 0 D , AND WILSON 441ping-mercury electrode at various drop rates, 549 at rotating electrodes, 550and a t cylindrical rni~ro-electrodes.~~1 The factors which affect the limitof sensitivity of the dropping-mercury electrode have been studied and itis concluded that, in electronic instrumentation, capillary " noise " is amajor factor.552A new polarograph has been devised for solutions of high resistance 553in which the iR effect is effectively eliminated, and which is suitable fornon-aqueous solutions; and a new polarising unit, with scanning unit andcurrent compensator, suitable for conventional and derivative polarography,has been de~cribed.5~~ For student use a simple semi-automatic polaro-graph has been devised.555Graphite 556 and carbon paste 557 electrodes have been successfully usedfor analysis of several inorganic and organic systems and an accuracy com-parable with that of the dropping-mercury electrode has been claimed.The wide-bore electrode, used for determining dissolved oxygen, has beenimproved to cope with a wide range of flow rates.558 Reference electrodes innon-aqueous systems have been investigated and it was concluded that theS.C.E.is frequently not ~uitable.55~ A number of cells, devised for specialapplications, have been described and include a cell for flowing solutions,56oa microcell for hanging-drop voltammetry, 561 and a versatile, detachablethree-component cell.562Uraniumhas been studied in EDTA solutions over a wide range of pH,563 and inconcentrations down to 1 0 - 4 ~ at pH >6.5 in the presence of excess offerric ions and several other elements, with a fluoride base electrolyte.564A simple procedure for determining technetium in fission products con-sists of deposition from an alkaline citrate base into mercury drops whichthen fall into a lower layer of carbon tetrachloride. The activity producedby technetium-99 a t 140 kev is determined by y-spe~trometry.~~~ Ananodic procedure for determining manganese uses an alkaline tartrate solu-t i ~ n . ~ ~ ~ By pre-electrolysis at - 1.50 v (S.C.E.) under cathodic conditionsM.P. Simmonin, J . Chim. phys., 1960, 57, 161; R. Tamamushi, S. Momiyama,and N. Tanaka, Analyt. Chim. Acta, 1960, 23, 586.550 W. Vielstich, 2. analyt. Chem., 1960, 173, 84.551E. Morgan, J. E. Harrar, and A. L. Crittenden, Analyt. Chem., 1960, 32, 756.552 W. D. Cooke, M. T. Kelley, and D. J. Fisher, Analyt. Chem., 1961, 33, 1209.553P. Arthur, P. A. Lewis, N. A. Lloyd, and R. K. Vanderkam, Analyt. Chem.,554M. T. Kelley, D. J. Fisher, and H. C. Jones, Analyt. Chem., 1960, 32, 1262.555G. W. Drake and C. B. Johnston, J. Chem. Educ., 1960, 37, 240.556P. J. Elving and D. L. Smith, Analyt. Chem., 1960, 32, 1849.557 C. Olson and R. N. Adams, Analyt. Chim. Acta, 1960, 22, 582.558 R. Briggs and G. Knowles, Analyst, 1961, 86, 603.559 R.C. Larson, R. T. Iwamoto, and R. N. Adams, Analyt. Chim. Acta, 1961, 25, 371.5 6 0 W. J. Blaedel and J. H. Strohl, Analyt. Chem., 1961, 33, 1631; K. Koyama,561W. L. Underkofler and I. Shah, Analyt. Chem., 1961, 33, 1966.562D. K. Roe and C. J. Nyman, Chemist-Analyst, 1960, 49, 27.563 T. T. Lai and T. L. Chang, Analyt. Chem., 1961, 33, 1193; D. G. Davis, ibid.,564A. H. Verbeek, J. T. Moelwyn-Hughes, and E. T. Verdier, Analyt. Chim. Ada,565 D. L. Love and A. E. Greendsle, Analyt. Chem., 1960, 32, 780.56eH. A. Catherino and L. Meites, Analyt. Chim. Acta, 1960, 23, 57.Numerous papers have appeared on determination of metals.1961, 33, 488.Analyt. Chern., 1960, 32, 1053.p. 492.1960, 22, 570442 ANALYTICAL CHEMISTRYall the manganese is reduced to Mn(n).On reducing the voltage to -0.7 vthe manganese is oxidised and the diffusion current at 0.36 v (S.C.E.)is measured. Only iron interferes if the ratio of iron to manganese con-centrations is >lo. A simple procedure for manganese in glasses involvesfusion with ammonium fluoride and oxalic acid and then dissolution inhydrochloric acid and addition of ammonium hydroxide and sulphite; asuitable reduction wave was obtained.567 Niobium has been determined inhighly alloyed steels. After dissolution in acid and hydrolysis the niobicacid is separated and fused with potassium hydroxide. After adjustmentof the pH to 1.9 in the presence of EDTA it wave was obtained withEL = -0.65 v (mercury pool), which was free from interference from allother metals except molybdenum.568 Separation of niobic acid by a solvent-extraction method was used to determine this element in titanium ores andpigments.569 Until recently arsenic(m) in alkaline solution has not beenconsidered to be reducible; however, in a lithium hydroxide-lithium chloridesolution a well-defined wave was obtained which was claimed to be suitablefor analytical purposes.570 Potassium iodide has been reported as a goodbase electrolyte for arsenic(m) and gives linearity between id and concentra-tion over the range 0.06 and 0.8 mm~le/litre.~~l A simple procedure fordetermining antimony in refined lead has been claimed to be applicabledown to 10 p.p.m. After removal of lead as sulphate the solution is polaro-graphed.Tin tends to interfere if present in s i w c a n t amounts and theEs. values for arsenic and bismuth are suEiciently removed from that ofantimony [-0.32 v (S.C.E.)] tb avoid interference.572 Europium has beendetermined down to 20 p.p.m. in monazite and samarskite. After disso-lution, precipitation of lead, and separation of rare earths by conventionalmeans, the rare-earth oxides were dissolved in hydrochloric acid and ignited.The residue was dissolved in 0.1M-ammonium chloride. The wave a t-0.67 (S.C.E.) was used to determine the europium content ; apparentlythere were no interferences. 573No difficultyarises from a high ratio of nitrate to nitrite in an acid citrate buffer at pH 2.After destruction of the nitrite with hydrazoic acid and addition of uranylions the nitrate was determined.574 A method based on the formation ofnitroso-2-naphthol from nitrite and 2-naphthol has been used for determiningnitrites in bri11es.57~ Thiosulphate in photographic gelatin has been deter-mined down to 6 x l O - ( j ~ with a mean error of &5%.After the gelatinhad been warmed with 0-1N-potassium nitrate at 50" direct polarographygave a wave at -0.50 v (S.C.E.).576 Difficulties arose if iodides or tetra-667 M. s. Zakharov, A. G. Stromberg, and G. G. Rodnova, Zavodskaya Lab., 1960,26, 163.s69L. A. Balchin and D. I. Williams, Analyst, 1960, 85, 503.670 W. B. Swam, J. F. Hazel, and W. M. McNabb, Analyt. Chem., 1960, 32, 1064.671T. Matsumae and R. Nakashima, Analyt. Chim.Acta, 1961, 24, 192.572 V. T. Athavale, R. G. Dhaneshwar, M. M. Mehta, and M. Sundaresan, Analyst,s78 V. T. Athavale, R. G. Dhaneshwar, and M. M. Mehta, Analyt. Chim. A&, 1960,674R. Annirio and J. E. McDonald, Analyt. Chern., 1961, 33, 475.576 J. H. Dhont, Analyst, 1960, 85, 144.s7aV. Stefan, Chem. prumysl, 1960, 10, 126.Nitrite has been determined in the presence of nitrate.668D. J. Brindley, Analyst, 1960, 85, 877.1961, 86, 399.23, 71CARTWRIGHT, WESTWOOD, AND WILSON 443thionates were present. Studies of the thiocyanate ion have shown thatit produces a wave in 0-1N-perchloric acid with E, = +0.205 v (S.C.E.)suitable for analysis.577 Complex ions formed between thiocyanate ionsand mercury(@ have been studied, and the formulae of such ions and theirformation constants have been evaluated. 578 Sulphide and elementarysulphur have been estimated in viscose fibres by simple procedures.Totalsulphur was determined by treatment with sodium hydroxide to convertsulphur into sulphide, followed by addition of EDTA and polarographingfrom -0.2 to -1.0 v (S.C.E.). Elementary sulphur was determined simi-larly after removal of hydrogen sulphide and carbon disulphide by treatmentwith dilute sulphuric a ~ i d . ~ 7 ~I n the plastics field styrene monomer was rapidly determined in poly-styrene resins by dissolution in alcohol using tetrabutylammonium chloridein 75% alcohol solution;580 phthalate, fumarate, and maleate esters do notinterfere. Styrene has also been determined by conversion into the nitro-site with sodium nitrite and acetic acid. After addition of sodium acetatea well-defined wave [Et = -0.27 v (S.C.E.)] was pr0duced.5~1 A pro-cedure for determining terephthalic acid in mixtures of phthalic acidisomers down to O.lyo with accuracy utilised a O-lM-lithium hydroxide baseelectrolyte.A wave was produced by terephthalic acid at -1.93 v(S.C.E.).582 Dimethyl and dibutyl phthalates have been determined inpropellants where nitroglycerine interferes. Reduction of the “ nitrogly-cerine ” by metallic zinc or titanous chloride in alcohol was followed byaddition of tetramethylammonium hydroxide to precipitate metals beforepolarography. The first of the two waves at -1.65 v (S.C.E.) was used forquantitative purposes. Good results were obtained up to 2.39% of dimethylphthalate and 6.95% of dibutyl phthalate.583 Aromatic hydrocarbons havebeen studied in concentrated solutions of trifluoroacetic acid. Perylene,tetracene, anthracene, pyrene, 3,4-benzopyreneY and 1,Z-benzanthraceneall give two waves on reduction. The first wave is a reduction of the hydro-carbon ion which is rapidly followed by protonation, and the second wave isa reduction of the proton complex.584 Amino-compounds such as tyrosine,tryptophan, and phenylalanine have been determined by selective nitrationto their nitro-derivatives;5a5 full details are given for each of these com-pounds, singly and in mixtures. An indirect procedure for a-amino-acidsinvolved their reaction at controlled pH with copper phosphate.Afterremoval of excess of copper compound the copper chelates formed wereconverted into 1 : 1 copper-EDTA complexes which were determined polaro-graphically. The method was claimed to be accurate to 3% at 1 0 - 3 ~concentration, but capable of detecting 2 x 10 - 6 ~ q~antities.58~ Cystine577R. A. Plowman and I. R. Wilson, Analyst, 1960, 85, 222.578 C. J. Nymam and G. S. Alberts, Analyt. Chem., 1960, 32, 207.570R. P6cenJi and V. NedvZidovS, Chem. prumysl, 1960, 10, 165.s80 W. M. Apes and G. C. Whitnack, AnaZyt. Chem., 1960, 32, 358.681V. i%divec and J. Flek, Coll. Czech. Chem. Comm., 1960, 25, 1223.582M. E. Hall and R. C. McNutt, AnaZyt. Chem., 1960, 32, 1073.583 J. Townend and E. Macintosh, Analyst, 1961, 86, 338.684 W. I. J.Aalbersberg and E. L. Mackor, Trans. Paraday SOC., 1960, 56, 1351.686D. Monnier, J. Vogel, and P. E. Wenger, Andyt. Chim. Acta, 1960, 22, 369.686 W. J. Blaedel and J. W. Todd, AnaZyt. Chem., 1960, 32, 1018444 ANALYTICAL CHEMISTRYand cysteine have been estimated directly in wool hydrolysates preparedwith sulphuric acid, by using cathodic and anodic waves respectively, withan accuracy of -+O-1 mg. on 30 mg., by means of a standard additionmethod.587 Thioethanolamine and its disulphide have been determined inthe presence of each other to within 2% at the level of 7-5 x 10-6M-con-centration, with one species in hundred-fold excess. At pH 7.4, thioethanol-amine gives a wave at -0.42 v and its disulphide at -0.62 v (S.C.E.).58*A number of hydroxy-triphenylmethane dyes have been shown to give a2-step reduction at pH 7 which is suitable for estimation and has beenapplied to aurines, eriochromes, chromoxanes, and naphthochrome~.~~~The behaviour of anumber of metal ions in liquid ammonia has been studied by using lithiumperchlorate as base electrolyte.590 Ethylenediamine has also been reportedto give good curves for many metal species, sodium nitrate or lithium chloridebeing used as electrolyte. 591 Similarly N-methylacetamide with tetra-ethylammonium bromide was satisfactory and a mercury pool made a suit-able reference electrode.592 Benzene-methanol mixtures were used todetermine several metal naphthenates, tallates , and octanoates in paintdriers. 593 Anodic studies of aromatic and heterocyclic hydrocarbons havebeen made in acetonitrile by using a rotated platinum electrode. The effectsof substitution on E, values were shown and techniques were devised foranalyses of mixtures of these compounds.594Several reviews onthese rapidly expanding fields have appea,red including recent generaldevelopments, 5g5 oscillographic applications ,5969 597 and alternating currentmethods.598 Much theoretical study has been promoted and is increasing.A full examination of variation in frequency and its effects on the symmetryand height of the peaks produced has been made, and the effects of variableson the analytical use of the peaks have been discussed.599A modification t o an existing d.c.polarograph has been made whichpermits it to be used as an a.c.instrument, The a.c. unit is separate andis made non-floating by earthing the negative side. When a mercury poolwas used accurate placement of the dropping-mercury electrode was neces-sary t o obtain reproducibility. High sensitivity was claimed.600 A.c.voltammetry using harmonic measurements has been demonstrated, 601 andPolarography in non-aqueous media is developing.A.c., cathode ray, and other polarographic methods.687 L. Benikk, 2. analyt. Chem., 1960, 175, 244.688 E. C. Chevalier and W. C. Purdy, Analyt. Chim. Acta, 1960, 23, 574.aE9M. Matrka, F. NavrBtil, and C. Figar, Chem. prumysl, 1960, 10, 129.a9oW. Hubiski and M. Dabkowska, Analyt. Chem., 1961, 33, 90.aglG. Schober and V. Gutmann, 2. analyt. Chem., 1960, 173, 2.aSsD.E. Sellers and G. W. Leonard, Analyt. Chem., 1961, 33, 334.69sE. J. Kuta, Analyt. Chem., 1960, 32, 1065.696G. W. C. Milner, Chimia (Switz.), 1960, 14, 106.ss6G. F. Reynolds, 2. analyt. Chern., 1960, 173, 65; M. Herrmann, ibid., p. 21.697 G. C. Whitnack, J . Electroanalyt. Chem., 1961, 2, 110.6g8H. Schmidt, 2. analyt. Chern., 1960, 173, 73.H. H. Bauer, J . Electroanalyt. Chem., 1961, 2, 66.6o0 W. F. Head, Analyt. Chim. Acta, 1960, 23, 297.601 H. H. Bauer, J . Electroanalyt. Chem., 1960, 1, 256; D. E. Smith and W. H.J. W. Loveland and G. R. Dimeler, Analyt. Chem., 1961, 33, 1196.Reinmuth, Analyt. Chem., 1961, 33, 482CARTWRIGHT, WESTWOOD, AND WILSON 445solid electrodes have been successfully applied with a lower limit of2.7 x 1 0 - 6 ~ for many systems.6o2Lead, cadmium, and zinc have been determined in large excess of in-dium 603 in a 0.5~-ammonium nitrate base.Good separation of the leadand cadmium peaks was obtained but the latter tended to be affected bythe indium peak. In M-phosphoric acid the indium peak disappearedowing to complex formation.Studies of isomeric organic compounds, e.g., o-, m- and p-nitrophenols 604and rn- and p-nitr~anilines,~~~ have shown the resolving power of thistechnique.Increasing use has been made of the cathode-ray polarograph in metal-lurgical problems. Very pure silicon was analysed, and procedures for10-6% of lead, cadmium, iron, copper, nickel, thallium, bismuth, and zincwere described.606 Lead has been determined in zirconium and its alloysdown to 10 p.p.m.607 Copper and iron have been determined in high-purity aluminium.608 Iron and steels have been analysed for copper,lead,609 and tin.610Anion determinations include that of cyanide 611 in O.lM-sodiumhydroxide down to 0.05 pg./ml., and iodate and periodate in a number ofbase electrolytes.612 Several explosives have been examined and simul-taneous determinations have been devised such as that of N.G.and D.N.G.,61Sand of R.D.X. and P.E.T.N.614The limits of applicability and sensitivity of the square-wave methodhave been discussed.615 It has been adapted to the determination of copperand lead in indium arsenide down to 0.1 p.p.m. of copper and 0.2 p.p.m.of lead.616 Plutonium down to 3.7 x 10-6M-concentration has also beendetermined in acid solution.617 Uranium in sea water has been determinedby using an extraction process followed by examination in a perchloric-tartaric acid supporting electrolyte.618A number of studies 619 have been made of the anodic stripping techniquewherein the species is stripped out at high current density. The speciesthen redissolves anodically during a voltage scan and the current peakproduced gives a measure of the concentration of the original species. The602 D. E. Walker, R. N. Adams, and A. L. Juliard, Analyt. Chem., 1960, 32, 1526.603 T. Takahashi and H. Shirai, Talanta, 1960, 5, 193.604T. Takahashi and H. Shirai, Tdanta, 1961, 8, 177.605 J. Tirouflet and E. Laviron, 8. analyt. Chem., 1960, 173, 43.606F. A. Pohl and W.Bonsels, Mikrochim. Acta, 1960, 641.607 R. T. Clark, Analyst, 1960, 85, 245; D. F. Wood and H. A. Nichols, ibid., p. 139.608 J. S. Hetman, Analyt. Chim. Acta, 1960, 22, 394.609 P. H. Scholes, Analyst, 1961, 86, 116.H. Scholes, Analyst, 1960, 85, 392.611 J. S. Hetman, J . Appl. Chem., 1960, 10, 16.61aA. Berka and J. Doleial, Analyt. Chim. Acta, 1961, 24, 476.613 J. S. Hetman, Talanta, 1960, 5, 267.614 J. S. Hetman, Analyt. Chem., 1960, 32, 1699.615 F. von Sturm, 2. analyt. Chem., 1960, 173, 11.616 V. J. Jennings, Analyst, 1960, 85, 62.617K. Koyama, Analyt. Chem., 1960, 32, 523.G. W. C. Milner, J. D. Wilson, G. A. Barnett, and A. A. Smales, J . Electroanalyt.619 W. H. Reinmuth, Analyt. Chem., 1961, 33, 185; I. Shah and J. Lewinson, ibid.,Chem., 1961, 2, 25.p.187446 ANALYTICAL CHEMISTRYmethod has been applied to nickel in a thiocyanate medium and it wasclaimed that concentrations down to 5 x 1 0 - s ~ could be analysed.620By using a platinum or gold electrode, with a rotated mercury plated plati-num electrode, thallium and lead have been determined a t lo-'M levelin a 0.1M-nitrate solution.621 Iodide down to 4 x 1 0 - 8 ~ concentrationhas been determined at a silver electrode by a corresponding cathodicprocess.622New techniques which have received attention and are suitable forultra-small amounts of reducible species include pulse polarography, inwhich the square-wave voltage is replaced by polarising pulses of shortand the hanging-drop technique which has been applied to thedetermination of 0.01 p.p.m.of cadmium in uranium salts.624Radiochemistry.-It is impossible in a small space adequately to presentthe progress which has occurred in two years. Activation analysis hasincreased in popularity but the isotopic tracer method is still the mostwidely applied. Many applications do not appear in journals concernedwith analysis and hence may escape attention, particularly as they are oftenpresented a.s minor aspects of larger or differently oriented work.Several reviews have been published including a general review ofnucleonics, activation analysis, 626 radiochemical analyses of multiple-labelled sub~tances,~2' a valuable collection of individual reviews onseparate elements,628 and microchemical methods used in the U.K.AtomicWeapons Research Establishment over the past 6 ~ears.62~ Numerousmodifications in apparatus and techniques have occurred. Past neutron-activation analysis using 14 Mev neutrons produced by bombarding atritium target has been advocated as an alternative to pile irradiation whereappropriate. 630 An a-counter, suitable for determining plutonium insolution,631 and a large proportional counter spectrometer for studyingradioactive samples of very low activity,G32 have been described. Anall-Teflon flow cell for continuous monitoring of 45Ca in effluent streamshas been devised, though some adsorption by heavy metals may restrictits use.633Applications involving neutron activation continue to increase, particu-larly for minute traces of elements in metals.Morris and Killick havedevised a number of straightforward procedures which follow irradiationwith thermal neutrons in B.E.P.O. Osmium and indium in palladium and620M. M. Nicholson, Analyt. Chem., 1960, 32, 1058.621 S. Bruckenstein and T. Nagai, Analyt. Chem., 1961, 33, 1201.6 2 a I . Shah and S. P. Perone, Analyt. Chern., 1961, 33, 325.623 G. C. Barker and A. W. Gardner, 2. analyt. Chem., 1960, 173, 79.624 W. Kerntila, E. Rakowska, and 2. Kublik, J. Electroanalyt. Chem., 1960, 1, 206.625 W. Wayne-Mehke, A d y t . Chem., 1960, 32, 1 0 4 ~ .626A. H. W. Aten, Chem. Weekblad, 1960, 56, 94; D. Mapper, Chimia, 1960, 14, 241.627 N. Getoff, Osterr. Chem.-Ztg., 1960, 61, 101.628 Nat. Acad. Sci. Nuclear Sci., 1960, Nos. 3008, 3009, 3014, 3021, 3023, 3024, 3026,629 R.G. Monk and J. Herrington, Analyt. Ch.im. Acta, 1961, 24, 481.630R. F. Coleman, Analyst, 1961, 86, 39.631 J. T. Byrne and G. A. Rost, Analyt. Chern., 1961, 33, 758.632 J. T. Holloway, D. C. Lu, and D. J. Zaffarano, Rev. Sci. Instr., 1960, 31, 91.633 W. J. Blaedel and E. D. Olsen, Analyt. Chem., 1960, 32, 789.3027, 3028; 1961, 3018, 3025, 3030, 3032, 3033, 3035, 3036CARTWRIGHT, WESTWOOD, AXD WILSON 447platinum,634 and gold 635 and palladium 636 in platinum were determinedby using carrier techniques. The causes of possible interferences andmethods of avoiding them were discussed. Manganese in steels was deter-mined by a very short time of irradiation (10 minutes), thus avoiding sig-nificant activation of any of the other constituents.Owing to its highcapture cross-section (a 3 13.4 barns) an appreciable activity was quicklyacquired. By leaving the sample for 4 hours, species such as 52V, ‘Wu,51Ti, 94mNb, and 1OlmMo had decayed away, and 56Mn was counted by itsy-emission above 1.5 Mev.637 High-purity aluminium for use in reactorcores has been analysed for cadmium 638 by using a short time exposure.After irradiation the cadmium was separated by ion-exchange methods andprecipitated with carriers; a sensitivity of 1 part in lo9 parts was claimed.Copper, cadmium, nickel, tellurium, and zinc were determined in high-purity selenium.639 Owing to the short half-life of 65Ni (2.56 hours) a rapidprocedure was essential. Each metal was determined separately by its#$activity after precipitation with isotopic carriers.Similar procedureshave been used for determining minute traces of metals in rocks and meteor-ites. A radium separation from rocks was devised for silver and thallium,based on precipitation and electrodeposition, and counting as iodate andchromate respectively.640 The sensitivity claimed was 0.03 p.p.m. forsilver and 0-04 p.p.m. for thallium. Carriers and solvent extraction methodsbeing used to isolate the active species, tantalum 641 and rhenium 642 weresimilarly determined. Scandium 643 and vanadium 644 have also been deter-mined in rocks and meteorites in connexion with studies of the SkaargaardIntrusion of E. Greenland; cadmium 645 was also determined on the sameproject.The methods, which involved y-counting, gave close agreementwith results obtained for standard G1 and W1 rocks. The procedure €orvanadium was perforce very rapid since the isotope 52V has a half-life ofonly 3.76 minutes. Selenium and tellurium have also been determined inmeteorites after an irradiation of 1 week. The 75Se is readily detected anddetermined by its three intense y-photopeaks, and 127Te by its p-activity.646In the biological field, sodium, potassium, and phosphorus have been deter-mined down to 10-lo, and 10-lo g., re~pectively.~~7 Strontium hasbeen determined in alfalfa, rye-grass, milk powders, and bone ash by neutronactivation using the 87mSr isotope for measurement by its /I-activity. Onlya few hours’ activation was ne~essary.~~g634D.F. C. Morris and R. A. Killick, Talanta, 1961, 8, 129.635 D. F. C. Morris and R. A. Killick, Talanta, 1961, 8, 793.636 D. I?. C. Morris and R. A. Killick, TaZarLta, 1961, 8, 601.637 P. Bouten and J. Hoste, Talanta, 1961, 8, 322.638E. Ricci and W. D. Mackintosh, Analyt. Chem., 1961, 33, 230.63sA. I. Williams, Analyst, 1961, 86, 172.640 D. F. C. Morris and R. A. Killick, Talanta, 1960, 4, 51.641D. F. C. Morris and A. Olya, Talanta, 1960, 4, 194.64a D. F. C. Morris and F. W. Fifield, Talanta, 1961, 8, 612.643 D. M. Kemp and A. A. Smales, Analyt. Chim. Acta. 1960, 23, 410.644 D. M. Kemp and A. A. Smales, Analyt. Chim. Acta, 1960, 23, 397.64sL. I. Bilefield and E. A. Vincent, Analyst, 1961, 86, 386.646 U. Schindewolf, Geochim. Cosmochim.Acta, 1960, 19, 134.1 3 ~ ’ H. J. M. Bowen and P. A. Cawse, Analyst, 1961, 86, 506.648 B. A. Loveridge, R. K. Webster, J. W. Morgan, A. M. Thomas, and A. A. Smales,Analyt. Chim. Acta, 1960, 23, 154448 ANALYTICAL CHEMISTRYOther activation procedures reported include the determination offluoride in sodium chloride utilising the 19F(n,a)16N reaction by fast neu-t r o n ~ , ~ ~ ~ and the determination of iodine in silicon down 0.005 p.p.m. bya distillation procedure, absorption of the iodine into sulphite solution,and precipitation as silver iodide.65o Counting was done on a 2n counter.Ion-exchange techniques are frequently involved in the separation ofradioactive species. A separation scheme covering 35 elem.ents and usinga Dowex 50W cation-exchange resin has been put forward.651 Of theseover 30 are extracted to >goyo and 3 to >SOYo yields.Palladium, gold,mercury, and silver, however, cannot be accommodated in this scheme. Anumber of papers have been devoted to the determination of fission pro-ducts from uranium and plutonium. Tellurium was separated fromuranium on a Dowex-2 anion resin from a phosphoric acid solution withalmost quantitative yield.652 95Zn and 95Nb were removed from uraniumfission products by absorption on an anion-exchange resin Dowex 1-X4from a 0-3~-hydrofluoric acid solution, with yields of >99.6yo, and wererelatively free from other elements. 653 Irradiated plutonium metal afterdissolution was examined for 95Zr, g5Nb, l03Ru, 147Nd, and Pr. Plutoniumwas removed from the solution by an anion-exchange resin from stronglyacid solution and these elements were separated by precipitation techniques(zirconium and rhodium) and extraction techniques (niobium and ruthen-i ~ m ) .~ ~ ~ In the determination of radio-iodine in fission products, otheractivities were removed in one process by the cation-exchange resin Dowex50x8, and this was followed by an ion-exchange process based on silveriodide according to the scheme AgI + I* + AgI* + I, which occurs rapidly;the silver iodide was then counted.655 gOSr has been determined indirectlyin milk by a rapid method involving removal of alkali and alkaline-earthmetals by a cation-exchange resin. By use of an anion-exchange resin the90Sr daughter product, was then eluted with dilute acid, precipitated asoxalate, and counted in an anti-coincidence p-counter.Very good agree-ment with established methods was claimed. 656There has been an increased use of separation procedures using solventextraction, particularly by Maeck and his co-workers. Neptunium has beenextracted effectively as the tetra-alkylammonium trinitrate complex intoisobutyl methyl ketone from uranium fission-product mixtures, 657 and zincby extraction of the diethyldithiocarbamate complex into ethyl acetate.The latter indicated 658 that the fission yield of 72Zn on thermal neutronirradiation of 235U was 2.6 x 2-Thenoyltrifluoroacetone has beenused to extract zirconium from fission products as a complex in xylene and649 0. U.Anders, Analyt. Chem., 1960, 32, 1368.650T. Nozaki, H. Baba, and H. Araki, Bull. Chem. SOC. Japan, 1960, 33, 320.G51 W. J. Blaedel, E. D. Olsen, and R. F. Buchanan, Analyt. Chem., 1960, 32, 1866.662 L. Wish, Analyt. Chem., 1960, 32, 920.653A. C. Leaf, Talanta, 1960, 6, 265.654 J. W. T. Meadows, G. M. Mattack, and G. B. Nelson, Talanta, 1960, 6, 246.655 W. J. Maeck and J. E. Rein, Analyt. Chem., 1960, 32, 1079.s66 C. Porter, D. Cahill, R. Schneider, P. Robbins, W. Perry, and B. Kahn, Analyt.667 W. J. Maeck, G. L. Booman, M. C. Elliott, and J. E. Rein, Analyt. Chem., 1960,668 W. J. Maeck, M. E. KUSSY, and J. E. Rein, Analyt. Chem., 1961, 33, 235.Chem., 1961, 33, 1306.32, 605CARTWRIGHT, WESTWOOD, AND WILSON 449it is claimed to be highly selective from fluoride solution, and to be moreefficient than any other extractant .659 Frequently the extraction techniqueis combined with isotopic dilution. Phosphorus has been determined as32P by addition of potassium phosphate as carrier and extracted as phospho-molybdic acid in butanol-chloroform mixtures. The activity is extractedback into ammonia solution and is converted into magnesium pyrophosphatefor counting.660 Dithizone has been used for extraction of zinc 661 betweenpH 7-5 and 8.5 and of mercury 662 down to 10-6-10-7 g./ml.The theoryof the extraction process has been considered and the dependence on pHand other factors for dithizone has been el~cidated.~63 Uranium has beendetermined in sea water by a method involving addition of a stable isotopeand extraction into chloroform after complexing with 8-hydroxyquino-line. 664 Addition of 235U and mass-spectrometer measurements were alsoinvolved. A check with a fluorimetric method gave consistent results andconfirmed a value of 3.3, & 0.08 pg./ml.for water in the English Channel.A considerable number of papers involving the normal isotope-dilutionanalysis have continued to appear. A simple rapid method for iodine inthe presence of chloride and bromide involved addition of iodine and potas-sium iodide and shaking with carbon tetrachloride ; the extracted activitywas measured.665 Boron down to 0.001 pg. in silicon has been determinedby addition of a l o g - tracer. By electrolysis through a cation-exchangemembrane and determining the isotopic abundance with a mass spectro-meter this minute trace of boron was determined.666 235U in feedstocksolutions of uranium fuel has also been determined by isotopic dilutionfollowed by mass spectrometry; Z3,U and natural uranium were used astracers but the use of 233U gave more satisfactory re~ults.6~7 Tungstenhas been determined at low concentrations in high-alloy steels; afterhomogeneous precipitation from nitric acid-hydrogen peroxide solutionthe tungsten was determined either by counting or by spectrophotometry.668A variety of applications using liquid-scintillation methods continuesto appear. 95Zr and 95Nb have been readily determined by using a liquidscintillation spectrometer owing to ready resolution of the p-particle spectra,thus avoiding the necessity for corrections for self-absorption involved inother methods.669 Tritium in water and urine has been estimated downto 0.005 pc./litre by using low- background vessels. 670 Coloured solu-tions 671 such as Methyl Red, Bromothymol Blue, and blood digest have659 S. F. Marsh, W. J. Maeck, G. L. Booma.n, and J. E. Rein, Analyt. Chena., 1961,33. 870.660H. H. Ross and R. B. Hahn, Talanta, 1961, 8, 575.661 J. Star$ and J. RhiiEka, Talanta, 1961, 8, 296.662 J. RGiiEka and J. Star$, Talanta, 1961, 8, 535.663 J. Rhiidka and J. Starp, Talanta, 1961, 8, 228.66* J. D. Wilson, R. K. Webster, G. W. C. Milner, G. A. Barnett, and A. A. Smales,666M. D. Morachevskaya and B. V. Ptitsfn, Zavodslcaya Lab., 1960, 26, 269.666 D.C. Newton, J. Sanders, and A. C. Tyrrell, Analyst, 1960, 85, 870.667 R. K. Wester, D. F. Dance, J. W. Morgan, E. R.. Preece, L. J. Slee, and A. A.Smales, Analyt. Chim. Acta, 1960, 23, 101.66* G. Leliaert, J. Hoste, and Z . Eeckhaut, Rec. Trav. chim., 1960, '79, 557.669 J. D. Ludwick, Analyt. Chem., 1960, 32, 607.670F. E. Butler, Analyt. Chem., 1961, 33, 409.671 R. T. Herberg, Analyt. Chem., 1960, 33, 42, 1468.Analyt. China. Acta, 1960, 23, 505.450 ANALYTICAL CHEMISTRYbeen estimated by suitable procedures, and radioactive substances havebeen determined by suspension in a gel scintillator; in this way 90Sr, g o y ,36Cl, 22Na, la3Ba, 63Ni, W, and 3H have been determined.672Mass Spectrometry.-A recent review 673 indicates the developmentswhich have occurred, particularly in the United States of America and theU.S.S.R., since 1958.A two-stage mass spectrometer, devised for preciseabundance measurements in nuclear reactor technology, incorporates im-proved optics and a fast pulse-counting technique for detecting positiveions.674 Modifications to a commercial instrument produce a signal whichis a direct measure of the amount of material charged to it.675 Combina-tions of mass spectrometry and gas chromatography have appeared inwhich a conventional magnetic field spectrometer is coupled directly to achr0matograph.67~, 677Plutonium has been determined in irradiated uranium by an isotopicdilution method using 2 4 2 P ~ as a tracer with preliminary separation by anion-exchange technique, and measurement of the recovered plutonium bya MS5 ~pectrorneter.~’~ Uranium and plutonium have been determineddown to 10-8 g.in a device in which the ion beam is detected by an electron-multiplier and the pulses are accumulated in a modified pulse-analyser.The accelerating voltage is synchronised with the pulse sorter so that thedata can be printed out directly on a recorder.679 Very small quantitiesof lead, of the order of ( 1 p.p.m., in rocks and motor oils have beendetermined by a volatilisation procedure using 212Pb tracer to determineyields. BSOCorre-lations of mass spectra with structure have been made for a number ofaromatic alcohols and phenols, and spectral features suitable for qualitativeand quantitative analyses are discussed .681 Similar correlations for alde-hydes and acids,682 aliphatic esters,683 aromatic esters,684 and fluorinatedcyclic compounds 685 have been reported.Spectra of thiols and disulphideshave also been correlated in an investigation to determine the componentsresponsible for odour changes in beef.686Cyclo-pentane and cyclohexane derivatives in gasoline have been resolved, 687 andMost applications have occurred, of course, in the organic field.Numerous applications in the petroleum industry are of interest.6 7 2 s . Helf, C. G. White, and R. N. Shelley, Analyt. Chem., 1960, 32, 238.673V. H. Dibeler and R. M. Rees, Analyt. Chem., 1960, 32, 2 1 1 ~ .674 L. A. Dietz, C. F. Pachucki, J. C. Sheffield, A. B. Hance, and L. R. Hanrahan,‘375H.E. Lumpkin and J. 0. Beauxis, Analyt. Chem., 1960, 32, 1815.6 7 6 L . P. Lindeman and J. L. Annis, Analyt. Chem., 1960, 32, 1742.6 7 7 A. A. Ebert, Analyt. Chem., 1961, 33, 1865.6 7 8 R . K. Webster, A. A. Smales, D. F. Dance, and L. J. Slee, Analyt. Chim. Acta,679 G. W. Barton, L. E. Gibson, and L. F. Tolman, Analyt. Chem., 1960, 32, 1599.6 8 o R . R. Marshall and D. C. Hess, Analyt. Chem., 1960, 32, 960.681 T. Aczel and H. E. Lumpkin, Analyt. Chem., 1960, 32, 1819.6 8 z T . Aczel and H. E. Lumpkin, Analyt. Chem., 1961, 33, 386.683 J. H. Benyon, R. A. Saunders, and A. E. Williams, Analyt. Chem., 1961, 33, 221.6’34E. M. Emery, Analyt. Chem., 1960, 32, 1495.68sR. J. Majer, J . Appl. Chem., 1961, 11, 141.a8sE. J. Levy and W. A. Stahl, Analyt. Chem., 1961, 33, 707.687 H. E. Howard and W. C. Ferguson, Analyt. Chem., 1961, 33, 1870.Analyt. Chem., 1960, 32, 1276.1961, 24, 371CARTWRIGHT, WESTWOOD, AND WILSON 451the effectiveness of removal of mercaptans in naphthas can be readilymonitored.The presence of naphtheno-pyridine, -quinoline, and -carbazoles inpetroleum residues has been established and determined and the resultsagree closely with those obtained by ultraviolet spectroscopy.689 By useof a combination of high-temperature gas chromatography and massspectrometry, 67 components were identified. These included normalparaffins, and cyclopentyl and cyclohexyl derivatives. l7 An investigationof asphalt gave evidence of compounds from mass 24 to about 1900; exam-ination of the fragment spectra indicated that aromatic and heterocyclicnuclei were predominant.690 The fragments obtained in the mass spectraof dialkylboranes have been identified by using compounds labelled with1OB and de~terium.~~l An accurate method of determining tetramethyl-lead and tetraethyl-lead occurring together in gasoline has been claimed tobe much more rapid than chemical methods and to be suitable for routinework. 139211. Thermal methodsStress continues to be laid in both differential thermal and thermo-gravimetric analysis on the careful design of apparatus and strict controlof conditions necessary to ensure reproducible results. Garn,693 in a surveyof current differential methods, discusses sample holder design, sample sizeand geometry, thermal environment, and the influences of restricted diffu-sion and control of the atmosphere over the sample. Garn and Kessler 694indicate the advantages of analysis of effluent gases in thermal methods.The main application of the methods continues to be to inorganic materials,and an example of careful differential thermal analysis is the determinafionof the temperature of transformation between two forms of calcium oxide.695An apparatus has been described for differential thermal analysis at lowtemperatures. 696 There is a growing appreciation of uses in organic analysis.Chesters and Thompson 697 have carried out differential thermal analysesof a number of polysaccharides and have shown that a number of closelyrelated compounds, e.g. , amylose and amylopectin, give widely differingthermograms. They suggest that the technique may be used for poly-saccharide characterisation and for general identification of organic com-pounds. Routine differential thermal analysis of explosives is carriedout 698 in samples of less than 10 mg. by using a specially designed cell andfurnace.688 W. P. Hoogendonk and F. W. Porsche, Amlyt. Chem., 1960, 32, 941.689 C. L. Lau, Analyt. Chim. Acta, 1960, 22, 239.690R. J. Clerc and M. J. O'Neal, AnaZyt. Chem., 1961, 33, 380.691 C. 0. Wilson and I. Shapiro, Analyt. Chem., 1960, 32, 78.692 H. E. Howard, W. C. Ferguson, and L. R. Snyder, Analyt. Chew,., 1960, 32, 1814.693 P. D. Gem, AnaEyt. Chem., 1961, 33, 1247.694 P. D. Garn and J. E. Kessler, Analyt. Chem., 1961, 33, 952.695 B. V. S. Subba Rao, D. S. Datar, and Abde Mi, J . Sci. Ind. Res., India, B696 I. Proks and V. Sigke, C'hem. Zvesti, 1961, 15, 309.697 G. Chesters and S. 0. Thompson, Science, 1961, 133, 275.1961, 20, 347.R. N. Rogers, Microchem. J . , 1961, 5, 914: ANALYTICAL CHEMISTRYThermogravimetric methods of analysis have been reviewed by Lukas-zewski and Redfern899 who deal with the requirements of the thermalbalance, applications, and techniques. Guiochon 700 discusses errors indeductions from thermogravimetric measurements which are due to lackof appreciation of the conditions of thermal decomposition and of theinfluence of the products of decomposition. A thermogravimetric study ofmetal-gas reactions has been carried out with magnesium and aluminium.701The method is used widely to study the suitability of gravimetric procedures.The behaviour of plutonium and several of its compounds has been investi-gated 702, 703 and ranges of thermal stability have been determined. Theprecipitation of magnesium, potassium, and lead with 5-nitrobarbituric acidhas been studied, and conditions for its use as a gravirnetric reagent havebeen established;704 it has also been used in the determination of ethylene-diamine and quinine. 705 Determination of calcium, strontium, and bariumin a single sample of their oxalates by an indirect thermogravimetric tech-nique has been described,706 based on losses of weight of extraneous moisture,of water of crystallisation, and of carbon monoxide and dioxide.Since differential thermal analysis, thermogravimetric analysis, and dif-ferential thermogravimetric analysis (in which rate of gain or loss in weightis recorded) all require the same basic type of apparatus with controlledrate of heating over a wide range, and since the information derived fromea,ch is complementary to, and can best be interpreted in conjunction with,that derived from the others, it would seem that simultaneous determinationof rate of change in weight and in temperature is bound to be increasinglya'pplied. An apparatus for this purpose has been patented.707Thermometric titrations, in which the end-point is determined by a sharpchange in the shape of the curve connecting temperature of solution andvolume of titrant added, enable a wide variety of reagents to be used, andare unaffected by precipitation or gel formation. They have been used inthe titration of zinc, cadmium, and mercuric salts with aqueous ammoniaand sodium hydroxide 708 and in determining calcium in the presence ofmagnesium, by titration with ammonium oxalate, in limestone analysis. '09P. F. S. CARTWRIGHT.J. V. WESTWOOD.D. W. WILSON.699 G. M. Lukaszewski and J. P. Redfern, Lab. Practice, 1961, 10, 469, 552, 630.' 0 ° G. Guiochon, Analyt. Chew&., 1961, 33, 1124.701M. M. Markowitz and D. A. Boryta, Analyt. Chem., 1961, 33, 949.702 G. R. Waterbury, R. M. Douglass, and C. F. Metz, Analyt. Chem., 1961, 33, 1018.703 I. S. Sklyarenko and T. M. Chubukova, Zhur. analit. Khim., 1960, 15, 706.704A. Berlin and R. J. Robinson, Analyt. Chim. Acta, 1961, 24, 224.705A. Berlin and R. J. Robinson, Analyt. Chim. Acta, 1961, 24, 319.706 L. Erdey, F. Paulik, G. Svehla, and G. Liptay, 2. analyt. Chem., 1961,182, 329.707 F. Paulik, J. Paulik, and L. Erdey, B.P. Appln. 865,073/25.9.57.708 M. P. Ben-Yrtir, Trans. Chalmers Univ. Technol., Gothenburg, 1961, No. 236.'09 J. Jordan and E. J. Billingham, jun., Analyt. Chem., 1961, 33, 120

ISSN:0365-6217    

DOI:10.1039/AR9615800397

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

CRYSTALLOGRAPHY1. GENERALIT has been decided that these Reports should now contain a Crystallographysection every year, and this Report covers the year 1961. As usual, Crystallo-graphy is taken to comprise only those studies of crystals which can be madeby the diflraction of radiation, but excluding those concerned primarilywith defects in crystals. Most of our Report, therefore, concerns crystal-structure determinations, of which the great majority have been made byX-ray diffraction.An International Conference on Magnetism and Crystallography washeld at Kyoto during September 1961, and included a symposium on electronand neutron diffraction. A conference report will be published as a supple-ment to J . Phys. Soc. Japan. (Comparatively few papers dealt with crystalor molecular structures.) Abstracts of the papers presented a t the FifthInternational Congress of Crystallography appeared in the December 1960issue of Acta Crystallographim,.No attempt will be made to summarisethem now, as in most instances fuller accounts of the work will appear inthe literature. An indication of the direction in which crystallography isprogressing can however be given by listing the numbers of papers presentedunder various headings : defects and mechanical properties, 97 ; inorganicstructures, 77 ; organic structures, 58 ; deformations and imperfections, 36 ;apparatus and techniques, 36 ; thermal motion in crystals, 34 ; crystalgrowth and morphology, 24; structures of metals and alloys, 23; electrondiffraction, 22 ; mineral structures, 22 ; proteins, 19 ; methods of structuredetermination, 19 ; neutron diffraction, 17 ; identification and documenta-tion, 14 ; phase transformations, 13 ; space-group theory, 12 ; order-disorderphenomena, 10; various other topics, about 30 in all.Review articles of interest have appeared on “ Crystallography andStructure”,l and on X-ray crystallography as a meeting place of thesciences.2 A review of liquid crystals, with many references, has been madeby Chi~tyakov,~ and Aleksandrov and Ryzhova 4 have reviewed the subjectof the elastic constants of crystals, with some comments on the (unorthodox)theories of Laval, Raman, and others.Instruments.-A more complete account of the Arndt-Phillips auto-matic X-ray diffractometer has now appeared.Wooster has describedan automatic version of the Wooster-Martin instrument, and re+iews otherautomatic diffractometers in the same article. New high-temperaturecameras and camera attachments have been described,’ and a cryostat forW. Nowacki, Chimia (Switz.), 1961, 15, 411.H. Lipson, Contemp. Physics, 1960, 1, 370.J. G. Chistyakov, KristallograJiya, 1961, 5, 962.U. W. Arndt and D. C. Phillips, Acta Cryst., 1961, 14, 807.W. A. Wooster, Kristallogra$ya, 1960, 5, 375, 788.J. V. Smith and W. L. Brown, 2. Krist, 1961, 115, 93; B. A. Hatt, P. J. C.4 K . S. Aleksandrov and T. V. Ryzhova, Kristalbgrafiya, 1961, 6, 289.Kent, and G. J. Williams, J . Sci. Instr., 1960, 37, 273454 CRYSTALLOGRAPHYtaking single-crystal photographs at 20” K.* An integrating mechanism forprecession cameras has been described.9 Some of the corrections involvedin obtaining precise lattice parameters have been discussed again.loTheom and Practice of Structure h&&,-The absolute configurationof a molecule can be determined by making use of the anomalous dispersionof X-rays ;ll when anomalous scatterers are present the structure ampli-tudes I F(h) I and I F(-h) I are generally unequal.Experiments on cad-mium sulphide have now demonstrated the analogous effect in neutrondiffraction. l2 Potentially useful anomalous scatterers for structure deter-mination include lithium-6, boron-10, cadmium, and a number of elements inthe rare-earth and actinide series. It has been shown that a Pattersonfunction whose coefficients are (I P(h) I - I F(-h) 1)2 will contain peaks atthe ends of vectors relating the anomalous scatterers.An application ofthis function in an investigation of two mercury derivatives of haemoglobin(using X-ray data) has been described.13Several papers on direct methods of structure determination have beenpublished, as well as a monograph l4 for the instruction of the practicalcrystallographer in the art. A method has been described by which thegeneral form of fundamental inequalities involving structure factors can bederived for any space group.l5 An extension of the “ non-negativity cri-terion ” has been discussed by Lofgren,l6 while Karle and Hauptman l 7have completed a series of theoretical papers on a unified programme forphase determination for centrosymmetric space-groups.The investiga-tion of the structure of 1,4-dihydronicofinamide 1* using certain of themethods given in Hauptman and Karle’s monograph l9 provided an illus-tration of the fact that direct methods, like others, can lead to a structurewhich is plausible but incorrect. It is, however, very interesting that ilcorrection could be made using other phase-determining formulae.2o Thedetermination of the structure of cellobiose 21 by the use of a machineprogramme for the calculation of the minimum function is a nokeworthyachievement. A programme for a similar purpose has been described inthe Russian literature.22 It has been shown that in certain circumstancesit knowledge of the structure amplitudes of two non-centrosymmetric iso-morphous crystals may be sufficient to solve the structure.23 A number of8 J.D. Forrester, J . Sci. Instr., 1961, 38, 153.BE. C. Lingafelter and J. M. Stewart, Rev. Sci. Imtr., 1960, 31, 399.10 L. S. Zevin, M. M. Umanskii, D. M. Kheiker, and Y . M. Panchenko, Kristalb-11 Ann. Reports, 1960, 57, 468, gives other references.12s. W, Peterson and H. G. Smith, Phys. Rev. Letters, 1961, 6, 7 .13 M. G. Rossmann, Acta Cyst., 1961, 14, 383.14 M. M. Woolfson, “ Direct Methods in Crystallography,” Clarendon Press, Oxford,15 T. Oda, S. Nays, and I. Taguchi, Actu Cryst., 1961, 14, 456.16T. Lofgren, Acta Cryst., 1961, 14, 434.17 J. Karle and H. Hauptman, Actu Cryst., 1961, 14, 105.18 J. L. Karle, Acta Cryst., 1961, 14, 497.19 H.Hauptman and J. Karle, “ Solution of the Phase Problem.20 J. Karle and H. Hauptman, Actu Cryst., 1959, 12, 404.21 R. A. Jacobson, J. A. Wunderlich, and W. N. Lipscomb, Acta Cryst., 1961,14,598.22V. J . Simonoc and B. M. Shchedrin, KristuZlograJiya, 1961, 6, 363.23 G. Kartha, Acta Cryst., 1961,14,680 ; D.M. Blow and M. G. Rossmann, ibid., p. 1195.gra$yu, 1961, 6, 348.1961.I. The Centro-symmetric Crystal,” Polycrystal Book Service, New York, 1953COCHRAN: QENERAL 455syntheses for the '' deconvolution of the Patterson function " have beendescribed, and compared with another.24 A report of the Conference onComputing Methods and the Phase Problem, which was held in Glasgow in1960, has now been published in book form.25 It should prove particularlyuseful to anyone devising machine programmes for crystallographiccalculations.Accurate Structure Anasysis, Electron Distribution, eke.-An electron-diffraction study of crystals of urea has been reported.26 The structure(in projection) has been the subject of several X-ray investigations 27 andhas also been determined by neutron diffraction.28 It is possibly the firstto be studied by all three diffraction techniques.The atomic co-ordinatesdo not altogether agree as well as they should from standard deviationscalculated by the various investigators on the basis of the internal consistencyof their results.Cruickshank has considered in more detail the corrections to bond lengthswhich may be made necessary by the angular oscillation of a molecule.29In hexamine the C-N bond length apparently changes from 1.464 a t 298" Kto 1.474 A at 34" K, but the corrected value remains constant at 1.477 8.30Anomalous results obtained in attempting to refine the structure of tetragonalbarium titanate have led to pessimistic conclusions about the possibilityof obtaining accurate results in circumstances where there is strong inter-action between co-ordinate and thermal parameter^.^^ This topic seemslikely to cause controversy.Ibers has emphasised the errors that canresult in making electron counts over limited volumes. The count mayeven exceed the number of electrons present, because of series terminati0n.3~The same author has examined the problem of bond lengths to hydrogen, asdetermined by electron diffraction.33 The potential maximum shouldapparently be moved outwards by about 0.03 A relative to the nuclei, butthis is not inconsistent with the shortening often found in X-ray work.A number of papers have been concerned with the problem of the calcu-lation of atomic scattering factors (f-curves) from improved atomic models.The f-curves for numerous atoms and ions of the iron-group transition serieshave been calculated from the Hartree-Fock distributions, and principalscattering factors were also computed for the 3d-electrons of those atomscontaining non-spherical charge distributions. 34 Curves have also been cal-culated from analytical Hartree-Fock functions for the helium-like systems24 S. Raman, Acta Cryst., 1961, 14, 148; R.Srinivasan, ibid., p. 607; R. Srinivrtsanand C. Aravindakshan, ibid., p. 612.25 " Computing Methods and the Phase Problem in X-Ray Crystal Analysis,"ed. R. Pepinsky, J. M. Robertson, and J. C. Speakman, Pergamon Press, Oxford, 1961.2sA. N. Lobachev and B. K. Vainshtein, KristallograJiya, 1961, 6, 396.27 P. Vaughan and J. Donohue, Acta Cryst., 1952, 5, 530; R. Gilbert and K. Lorn-dale, ibid., 1956, 9, 697; H. J. Grenville-Wells, ibia?., p. 709; N. Sklar, M. E. Senko,and B. Post, ibid., 1961, 14, 716.28 J. E. Worsham, H. A. Levy, and S. W. Peterson, Acta Cryst., 1957, 10, 319.2aD. W. J. Cruickshank, Acta Cryst., 1961, 14, 896.30L. N. Becka and D. W. J. Cruickshank, Acta Cryst., 1961, 14, 1092.3lH. T. Evans, Acta Cryst., 1961, 14, 1019; S.Geller, ibid., p. 1026.32 J. A. Ibers, Acta Cryst., 1961, 14, 538.33 J. A. Ibers, Acta Cryst., 1961, 14, 853.34 R. E. Watson and A. J. Freeman, Acta Cryst., 1961, 14, 27; A. J. Freeman andR. E. Watson, ibid., p. 231456 CRYSTALLOGRAPHYH-, He..C4 +, 35 Results obtained by the poly-determinantal method forNa+, Ne, and F- have been used to assess the importance of electroncorrelation effects other than exchange on the charge distributions andtherefore on the f - ~ u r v e s . ~ ~ The Thomas-Fermi-Dirac model has beenused to calculate the f-curves for electron scattering for atoms of atomicnumber 20 and greater.37 Magnetic scattering of neutrons has been usedto measure the aspherical distribution of 3d-electrons in, for example, Ni2+,and thereby provides a check on the accuracy of such calculation~.~8 Polar-ised neutron beams have been used in some instances to determine thef-curves of the " magnetic " electrons.39The electron distribution in diamond has been recalculated from theX-ray data, but the conclusions drawn from this have been ~riticised.~OThe electron distribution in cuprous oxide has been determined, with anaccuracy which is claimed to show that the oxygen is doubly i ~ n i s e d .~ ~The electron distribution in calcium hydroxide has been determined withsufficient accuracy to locate the hydrogen atom.42 Banyard and March 44have compared the electron distribution in the ammonium ion in crystalsof NH4HF, (as determined by McDonald 43) with a theoretical model forthe spherical average density, and find moderate agreement.Magnetic Struches.-The results of several investigations of magneticstructures by the magnetic scattering of slow neutrons have been reported.I n Mn4N, the nitrogen is at the centre of a cube with manganese atoms atcube corners and face centres. The structure is ferromagnetic, the cornermoment of 3.5 ,uB being anti-parallel to the three face-centre moments eachof 0.8 pB.45 The magnetic structure of 3d-transition-metal double fluoridesKMF,, with M = Cr, Mn, Fe, Co, Ni, Cu, have been in~estigated.~~ Themanganese, iron, cobalt, and nickel compounds have the bivalent %-ioncoupled antiferromagnetically to six nearest neighbours, the chromiumcompound has a different structure, and the copper compound showed nomagnetic scattering.The arrangement of the majority is the same as indouble oxides of tervalent 3d-ions, e.g., CaMnO,. Lattice distortions inthese compounds have been the subject of an X-ray in~estigation.~' Mag-netic ordering in trifluorides of 4d-transition elements has been investigated. 48Molybdenum trifluoride has magnetic properties very similar to those ofthe corresponding 3d- compound, chromium trifluoride. The magnetic35 J. N. Silverman, 0. Platas, and F. A. Matsen, Acta Cryst., 1960, 13, 539; C. M.36 B. Dawson, Acta Cryst., 1961, 14, 1117, 1120.37 J. A. Ibers and B. K. Vainshtein, Kristallografiya, 1959, 4, 641.38 H. A. Alperin, Phys. Rev. Letters, 1961, 6, 55.39R. Nathans, J . Appl. Phys., 1960, 31, 3505; S.Pickert and R. Nathans, ibid.,40 G. B. Carpenter, J . Chem. Phys., 1960, 32, 525; J. A. Ibers, ibid., 1960, 33, 299.41T. Suzuki, J . Phys. SOC. Japan, 1961, 16, 501.42H. E. Petch, Acta Cryst., 1961, 14, 950.43T. R. R. McDonald, Acta Cryst., 1960, 13, 113.a4K. E. Banyard and N. H. March, Acta Cryst., 1961, 14, 357.45 W. J. Takei, G. Shirane, and R. C. Frazer, Phys. Rev., 1960, 119, 122.46 V. Scatturin, L. Corliss, N. Elliott, and J. Hastings, Acta Cryst., 1961, 14, 19.4'K. Knox, Acta Cryst., 1961, 14, 583.48 M. K. Wilkinson, E. 0. Wollan, H. R. Child, and J. W. Cable, Phys. Rev., 1961,Womack, J. N. Silverman, and F. A. Matsen, ibid., 1961, 14, 744.p. 3725.121, 74COCHRAN: GENERAL 457moment is that appropriate to an ion with three unpaired d-electrons.However, neither palladium trifluoride nor ruthenium trifluoride showedmagnetic properties similar to those of the corresponding trifluorides of theiron group.Nickel oxide has a ferromagnetic sheet structure with atomicmoments in (1 11) planes, alternate sheets having reversed direction^.^^ Nomagnetic scattering could be detected from a specimen of titanium(rrr)oxide, although it has been thought to be antiferr~magnetic.~~ The mag-netic structure of stoicheiometric ferrous sulphide has been determined, intwo antiferromagnetic phases. Magnetic moments are parallel to a crystallo-graphic axis in the low-temperature phase, and perpendicular to this axisin the other.51Hydrogen Bonding.-Three structures are now known in which watermolecules might be thought to be connected by very short hydrogen bonds,2.48 8 in biuret hydrate, 2.27 8 in caffeine monohydrate, and 2-55 A inthymine m~nohydrate.~~ The correct explanation appears to be that thesites of the water molecules are only partly occupied, and a sequentialarrangement of water molecules at a separation of about 2.7 8 is interruptedafter a run of about six molecules.Adjacent chains have their extremitiesin close contact. The sequence is broken by the impossibility of forminga hydrogen bond with an oxygen atom of the organic molecule. Fig. 1shows a projection of part of one of the possible distributions of watermolecules in thymine monohydrate.A bent hydrogen-bond model has been suggested for the structure ofice (ice I).It retains the value 104.5" for the H-O-H angle, and is asconsistent with the neutron diffraction data as is the Pauling Anaccurate determination of the structure of potassium hydrogen maleate hasbeen made.54 The electron distribution is consistent with the assumptionthat the proton is a t the centre of the intramolecular hydrogen bond, whoselength is 2-44 8. The results are in good agreement with an earlier but lessextensive investigation by neutron diffraction. 55 Relevant results alsoappear in later sections.Ferroelectric Crystals.-The structure of the low-temperature phase ofsodium nitrite has been determined accurately by neutron diffraction, and isin good agreement with the results of earlier X-ray studies.56 The observedspontaneous polarisation is not at all in agreement with a calculation basedon a fully ionic model, as was to be expected. It has been pointed out 57that the structures of certain phases of ammonium iodide and of ammonium49H.A. Alperin, J . Appl. Phys., 1960, 31, 354; W. L. Roth, ibid., p. 2000.G. Shirane, S. J. Pickart, and R. Newnham, J . Phys. and Chem. Solids, 1960,13, 166.51 A. F. Andersen, Acta Chem. Scand., 1960, 14, 919.s2 D. J. Sutor, Acta Cryst., 1958, 11, 453; R. Gerdil and R. E. Marsh, ibid., 1960,13, 165; R. Gerdil, ibid., 1961,14, 333; E. W. Hughes, H. L. Yakel, and H. C. Freeman,ibid.. D. 345.i3LR.~Chidarnharan, Acta C ~ y s t . , 1961, 14, 467; P. G. Owston, Adv. Phys., 1958,7. 171. -..54 S. F. Darlow and W.Cochran, Acta Cryst., 1961, 14, 1250; S. F. Darlow, ibid.,'j5S. W. Peterson and H. A. Levy, J . Chem. Phys., 1958, 29, 948.5eM. I. Kay and B. C. Frazer, Acta Cryst., 1961, 14, 56.57A. S. Sonin, Kristallografiya, 1961, 6, 137.p. 1257458 CRYSTALLOGRAPHY. *7.--- - . .-c..: 311...... *... -. . ;?.. -FIG. 1. Possible arrangement of waler molecules in the crystul structwe of thyminemonohydrate.(Reproduced, with permission, from R. Gerdil, Ada Cryst., 1961, 14, 333.)bromide provide examples of antiferroelectrics of the type envisaged byKittel in the first publication on the s~bject.~8 Shuvalov and Sonin 59 havegiven their own formal definition of an antiferroelectric, and have discussedthe crystallographic classification, domain-structure geometry, possible pointKittel, Phys.Rev., 1961, 82, 729.S O L . A. Shuvalov and A. S . Sonin, KristalEogra$ya, 1961, 6, 258COCHRAN: GENERAL 459symmetry, and other features of such crystals. The crystal structure of thehigh-temperature (non-ferroelectric) phase of thiourea has been determinedby electron diffraction, and the hydrogen atoms have been located.60 Thecritical scattering from a crystal near its Curie point, and the variation ofthe intensities of the Bragg reflections in the neighbourhood of the Curietemperature, have been studied by using crystals of triglycine sulphate andof sodium nitrite.6l The results can be explained in terms of a transitionfrom a disordered to an ordered phase with decreasing temperature, theordering being completed in a range of several degrees below the transitiontemperature.Thermal lMects.-Most information under this heading is obtained frommeasurements of the intensities of the Bragg reflections (ie., elastic scatter-ing), but an increasing number of studies is concerned with the thermaldiffuse scattering of X-rays or of slow neutrons (i.e., inelastic scattering).It has been shown that in certain circumstances the intensity of a Braggreflection may actually increase with increasing temperature.This is thecase for the (200) reflection from fluorite, and results from the different ratesof variation of the Debye-Waller factors of calcium and of fluorine withtemperature.s2 Thermal vibration in urea crystals at -140" and +ZOOhas been studied,2' with results which do not agree very well with thoseobtained from neutron diffraction measurements.28 Only the NH.m.0 bondsshowed a significant change in length with temperature.The results ofDegeilh and Marsh on dioxopiperazine have been reanaly~ed.~~ The mole-cules are joined by hydrogen bonds to form ribbons, and it is found that thelargest translational and librational movements, with each molecule behav-ing as a quasi-rigid unit, are out of the plane of the ribbon, which thereforebehaves rather like an elastic ribbon. Lonsdale and Milledge 64 haveemphasised that very accurate intensity measurements are required todefine the magnitudes and directions of the principal axes of thermal vibra-tion of an atom, and have illustrated this by comparing results given by twoindependent sets of data for anthracene.Although the conventionalR-factors were 0.036 and 0.049 respectively, there were large differencesbetween the directions of the principal axes of certain atoms. The questionof the inversion temperature for thermal scattering by various crystals) andits relation to the Debye characteristic temperature, has been examinedtheoretically. 65The diffuse scattering of X-rays by crystals of anthracene has beeninvestigated) and the occurrence of " continuous domains " explainedqualitatively in terms of independent molecular vibration and libration.66A thorough study of the lattice dynamics of aluminium has been made byinelastic scattering of neutrons. The frequencies and damping factors ofV.F. Dvoryankin and B. K. Vainshtein, KristaZZografiyu, 1961, 5, 589.I. Shibuya and T. Mitzui, J . Phys. SOC. Japan, 1961, 16, 479; I. Shibuya, ibid.,p. 490.62 B. E. Warren, Actu Cryst., 1961, 14, 1095.63 K. Lonsdale, Acta Cryst., 1961, 14, 37.64 K. Lonsdale and J. Milledge, Acta Cryst., 1961, 14, 59.65 M. L. Canut and J. I;. Amoros, Proc. Phys. SOC., 1961, 77, 712.6 6 S . Annaka and J. L. Amoros, 2. Krist., 1960, 114, 423460 C R Y S TALL 0 GRAPH Ymany normal modes were investigated as a function of temperat~re.~~ The" X-ray diffraction spikes " from certain diamonds were originally inter-preted as an effect of the lattice vibrations, but it is coming to be acceptedthat they are associated with the occurrence of nitrogen as an impurity.There has been another spiky exchange on the subject.68w.c.2. INORGANIC STRUCTURESElements.-New high-pressure modifications of 4He and 3He, stable attemperatures of about 16" K and 19" I(, respectively, have been found;both have the face-centred cubic close-packed structure.6s Solid nitrogenconsists of dinitrogen molecules, the N-N bond-length being little differentfrom its value in the gas phase, arranged on a face-centred cubic lattice;the structure is made irregular by stacking faults.70Several authors 71 have discussed the bond lengths in orthorhombicsulphur (S8), the preferred value being 2.048 & 0.002 8, with the bond angle107'55' & 8'. The rhombohedra1 form of sulphur has been shown toconsist of S, hexagons of the chair form, with S-S = 2.057 & 0.018 8, andthe angle 8-S-S = 102.2" -J= 1.6".It is deduced that the s6 ring is slightlymore strained than the S, ring in orthorhombic sulphur.72Uranium crystallises with orthorhombic symmetry, 73 the closest U-Udistance being 2.751 8. Americium occurs in both double-hexagonal close-packed and face-centred forms.74Hydrides.-The fluorite-type structure has been found for the unstableNbH2,'5 whilst AcH is face-centred cubic, presumably with the sodiumchloride-type of structure.76 The deuterides AlTh,D,(n = 0--4), however,are interstitial compounds forming a range of solid solutions; neutron-diffraction studies show that the deuterium atoms occupy the centres ofdeformed tetrahedra of thorium atoms, and apart from some expansionof the lattice parameters the AlTh, structure remains unaffected by theaddition of the deuterium atoms.77Boron Hydrides.-Most of the boron hydride complexes studied conformto the usual topological rules for this type of compound, and recent papersreport the structures of: [B,H,]-, which has a triangular structure ofRH, groups linked by one normal and two hydrogen bridges;7s [Bl,H12]-and S.Holmryd, ibid., 1960, 17, 369.R. L. Mills, ibid., p. 546.6 7 K. E. Larsson, Arkiv. Fys. Xverige, 1960, 16, 504; K. E. Larsson, U. Dahlborg,s*Y. Yoneda, Nature, 1961, 191, 1187; F. C. Frank, ibid., p. 1188.g9 R. L. Mills and A. F. Schuch, Phys. Rev. Letters, 1961, 6, 263; A. F. Schuch and70 E. M. Horl and L. Marton, Actu Cm~st., 1961, 14, 11.7 1 S.C. Abrahams, Actu Cryst., 1961, 14, 311; A. Caron and J. Donohue, dibid.,72J. Donohue, A, Caron, and E. Goldish, J. Amer. Chem. SOC., 1961, 83, 3748.73A. H. Cash, E. W. Hughes, and C. C. Murdock, Acta Cryst., 1961, 14, 313.74 D. B. McWhan, J. C. Wallmann, B. €3. Cunningham, L. B. Asprey, F. H. Ellinger,and W. H. Zachariasen, J. Inorg. Nuclear Chem., 1960, 15, 185.76G. Brauer and H. Muller, J. Inorg. Nuclear Chem., 1961, 17, 10.2.7 6 J. D. Farr, A. L. Giorgi, M. G. Bowman, and R. K. Money, J. Inorg. Nuclearp. 548; A. S. Cooper, W. L. Bond, and S. C. Abrsthams, ibid., p. 1008.-Chciii., 1961, 18, 42.7 7 J. Bergsma, J. A. Goedkoop, and J. H. N. van Vucht, Acta Cryst., 1961,14, 223.78C. R. Peters and C. E. Nordman, J. Amer. Chem.SOC., 1960, 82, 5758OWSTON : INORGANIC STRUCTURES 461which has icosahedral symmetry;79 B,H,,*NCMe 8O and B,H,.81 A furthergeneral paper on the topology of B, and B, hydrides has been published.a2B,,H,, has a new type of structure (1) consisting of two square pyra,midsjoined apex-to-apex. 83The compound (BH,),(NMe,), appears in a subsequent section.246Borides and Carbides.-A comprehensive survey of the borides andsilicides of the transition metals has appeared.84The structure of metal borides commonly consists of a nearly close-packed arrangement of metal atoms with boron atoms in some of theinterstices. The boron atoms have six metal atoms as nearest neighbours,with three others further away, in the trigonal arrangement shown (inidealised form) in (2).Further examples of this type of co-ordination areprovided by Pd5B, and Pd,B,85 and Re3B,B7 and a similar struc-ture is found in Pd,Si.s8Interstitial compounds of a different type have also been d e s ~ r i b e d ; ~ ~they consist of B,, icosahedra which are packed in a roughly face-centredcubic arrangement, with interstitial groups which may contain one orthree atoms, e.g., in B,,S, B12Si3, B,,P, (i.e., B,,*BP,), BI3AsZ, and B1302.Bl2Be has a tetragonal structure with beryllium atoms lying between B,,icosahedra. 90The dodecaborides, MB,,, of some rare-earth metals have been similarlydescribed as having metal atoms packed between cubo-octahedra of twelveboron atoms, and here the stability of the lattice is a sensitive functionof the size of the metaLg1’@ J.A. Wunderlich and W. N. Lipscomb, J. Amer. Chem. SOC., 1960, 82, 4427.s°F. E. Wang, P. G. Simpson, and W. N. Lipscomb, J. Amer. Chem. SOC., 1961,82 W. N. Lipscomb, J . Phys. Chen,., 1961, 65, 1064.83R. Grimes, F. E. Wan& R. Lewin, and W. N. Lipscomb, Proc. Nut. Acud. Sci.,84B. Aronsson, Actu Chem. Scund., 1960, 14, 1414.85E. Stenberg, Actu Chem. Scund., 1961, 15, 861.s6 J. helius, Actu Chem. Scund., 1960, 14, 2169.ssB. Aronsson and A. Nylund, Actu Chem. Scund., 1960, 14, 1011.90M. Elfstrom, Actu C h m . Scund., 1961, 15, 1178.slH. J. Becher, 2. urcorg. Chem., 1960, 306, 266.83, 491.P. G. Simpson and W. N. Lipscomb, J. Chem. Phys., 1961, 35, 1340.U.S.A., 1961, 47, 996.B. Aronsson, 34. Backman, and S.Rundqvist, Actu Chem. Scund., 1960, 14, 1001.V. I. Matkovich, J. Amer. Chem. SOC., 1961, 83, 1804; Actu Cryst., 1961, 14, 93462 CRYSTALLOGRAPHYA re-examination of CrjB4, which is isostructural with Ta3B4, hasshown that one of the B-B bonds is unusually short.92Ruthenium and osmium carbides have the same hexagonal structureas tungsten carbide;93 neutron diffraction studies 94 have shown that thetrue space-group symmetry of this structure-type is P6m2.In calcium carbide-( 111) the carbide ions have rotated considerably fromtheir orientation in calcium carbide-(I), but the positions of their centresare only slightly changed.95Aluminium oxide carbide, AI,CO, has been found to have a hexagonalstructure like that of wurtzite, with aluminium replacing zinc, and thesulphur atoms replaced half by carbon and half by oxygen; the structureas a whole is not regular, however.96 It is probable that this is the com-pound previously regarded as A1,O.Compounds of Nitrogen, Phosphorus, and Sulphur.-Neutron diffractionmethods have been used to confirm that there is statistical disorder insolid nitrous oxide, where the molecule may have either of two orientations,NNO and ONN, with nearly equal pr~bability.~~ They show also thatthe cyanide ions in solid potaspium cyanide rotate freely, with a C-Ndistance of 1.16An unexpected result of X-ray work on tetrameric phosphonitrilicfluoride (PNF,), is that the eight-membered (P4N4) ring (3) is planar.99The P-N distances (1.51 & 0.02 8) are equal and short, indicating con-siderable double-bond character; a further unusual feature is the largeangle of 147" at the nitrogen atom.By contrast the eight-membered ringof [PN(NMe,),], has an unusual puckered form with the P-N bonds allequal (1.59 b ) . 1 0 0 The nature of the bonding in phosphonitrilic compoundsis evidently not simple.In tetrathiazyl fluoride, (NSF),, the (N4S4) ring is also puckered butin a more normal manner.101 The N-S bonds are alternately long (1.65 b)and shorter (1.55 A), suggesting that there are alternate single and doublebonds ; the bond angles S-N-S (123") and N-S-N (1 12") give little indica-tion of strain in the ring. The puckered eight-membered ring of hexa-sulphur imide, S,(NH), (4) is symmetrical, and all the bond lengths andFP I F s, /N\ \;,q F\ ,N-s-N, //p*N.\:NqF 1 (4) (5)FF ( 3 )92 S.La Placa, I. Binder, and B. Post, J . Inorg. Nuclear Chem., 1961, 18, 113.93 C. P. Kempter and M. R. Nadler, J . Chena. Phys., 1960, 33, 1580.94 J. Leciejewicz, Acta Cryst., 1961, 14, 200.95N.-G. Vannerberg, Acta Chem. Scand., 1961, 15, 769.96 E. L. Amma and G. A. Jeffrey, J. Chem. Phys., 1961, 34, 252.97W. C. Hamilton and M. Petrie, J. Phys. Chem., 1961, 65, 1453.98N. Elliott and J. Hastings, Actu Cryst., 1961, 14, 1018.99H. McD. MeGeachin and F. R. Tromans, Chem. and Ind., 1960, 1131; J . , 1961,4777.loo G. J. Bullen, Proc. Chem. Xoc., 1960, 425.101 G. A. Wiegers and A. Vos, Acta Cryst., 1961, 14, 563OWSTON : INORGANIC STRUCTURES 463angles are normal for a single-bonded structure;102 the same is probablytrue of the related heptasulphur imide, S,NH.The molecule S3N202 is planar and is unusual in having a cis-configura-tion.103 The bond lengths and angles show that the structure is that of (5).An accurate analysis has been made of (PCF,),; the five-memberedring of phosphorus atoms is not planar and there is evidence of strain,partly because two of the bulky trifluoromethyl groups are cis to each other,and partly because of interactions between fluorine and phosphorusatoms.lo4Addition Compounds.-The 1 : 1 addition compound of 4-picoline andiodine consists of molecules Me*C,H,N*I-I ; the nitrogen and iodine atomsare collinear with d(N-I) = 2.31 A and d(1-I) = 2-83 8, and the N-1-1line makes an angle of 13" with the plane of the picoline ring.lo5 Similarly,iodine combines with the sulphur atom of benzyl sulphide so that the threeheavy atoms are collinear, d(S-I) = 2.78 8, d(1-I) = 2.82 8; the pyramidalconfiguration of the donor atom (sulphur) is here still more marked.lo6The 1 : 2 addition compound pyridine72I,, however, has a quite differentstructure.107 It is ionic, and is better formulated as [ (C5H,N),I]+13-,21, ;the positive ion is centrosymmetric and planar, with d(N-I) = 2-16 8,and the tri-iodide ions are bound together by the iodine molecules to forma three-dimensional network like that in heptaiodides.Many " addition compounds " should really be regarded as normdco-ordination complexes.In the complex [ Et,P(CS,)] the phosphorusatom donates a lone pair of electrons to the central carbon atom of carbondisulphide to form a compound in which all the bond lengths are normal;the carbon atom has approximately trigonal planar symmetry and thephosphorus becomes approximately tetrahedral.lo8 SeOC1, adds twomolecules of pyridine to give a molecule with square pyramidal co-ordina-tion round the selenium atom.109A different type of co-ordination is found in four ammonium complexes,which have been studied a t low temperatures.llO In NH4I,4NH, eachammonia molecule co-ordinates with a hydrogen atom of the ammoniumgroup, thus forming an ion [NH,,4NH3]+ held together by N-H-N hydro-gen bonds 2.96 A long.In NH4X,3NH3 (X = CI, Br, I) the centralammonium ion is similarly co-ordinated to the three ammonia moleculesand the halide ion, forming a neutral molecule.The structure of the addition compound A1,Br6,C6H6 gives no clearindication of the nature of the interaction between the aluminium bromideand benzene molecules, which appear to remain separate and distinct.111 ,lo2 J.Weiss, 2. apEorg. Chem., 1960, 305, 190.lo8 J. Weiss, 2. Naturforsch., 1961, 16b, 477.lo4C. J. Spencer and W. N. Lipscomb, Actu Cryst., 1961, 14, 250. loso. Hassel, C. Rsmming, and T. Tufte, Actu Chem. Scund., 1961, 15, 967.lo6C. Ramming, Actu Chem. Xcund., 1960, 14, 2145.lo' 0. Hassel and H. Hope,' Actu Chem. Scund., 1961, 15, 407.loeT. N. Margulis and D. H. Templeton, J . Amer. Chem. SOC., 1961, 83, 995.loaG. Nahringbauer and I. Lindqvist,, U.S.Dept. Com., Office Tech. Serv. P. B.ll1 D. D. Eley, J. H. Taylor, and S. C. Wallwork, J., 1961, 3867.Rept., 1958, 138710.I. Olovsson, Actu C'hem. Scund., 1960, 14, 1453, 1466464 CRY STALL0 GRAPHYOrganometallic Compounds.-In the structure of dichloro( norbornadiene)-palladium 112 the two double bonds of norbornadiene form n-type bondsto the metal atom, similar t o that formed by ethylene; the bond lengthsindicate that the bonds lose some of their double-bond character when thecomplex is formed. Cyclo-octatetraene forms a less symmetrical complex,(CO)3Fe(C8H,)Fe(CO),113 (6) in which each iron artom forms one strong andone weak n-type bond with the olefin.The molecule of butadieneiron tricarbonyl, (C,H,)Fe( CO),, is rather likethis cyclo-octatetraene complex divided into two.It differs in havingall four of the butadiene carbon atoms equidistant from the iron atom andin having all three C-C bond lengths equal (1.45 A); the n-electrons thusappear t o be completely delocalised and the compound is to be regardedas a n-complex with the whole butadiene molecule, and not a di-olefincomplex;ll4 the symmetry of the molecule is lower than that of the cyclo-pentadienylmetal tricarbonyls. Acrylonitrileiron tetracarbonyl is an olefincomplex, the nitrile group taking no important part in co-ordinating tothe metal.l15 The C=C bond, which co-ordinates with the metal atom, islonger than a normal double bond, and rather surprisingly for a non-symmetrical olefin the two carbon atoms are equidistant from the iron atom.The four carbonyl groups and the double bond forma trigonal bipyramid round the iron atom, with thedouble bond lying in the equatorial plane.Some further examples of “ sandwich ” com-pounds, conforming to well-known types, have beenstudied.ll6 I n the compound C,H,Mo(CO), six of the‘‘0 carbon atoms of the cycloheptatriene ring are joinedby short bonds to form a planar conjugated system,interrupted by the seventh, which is a CH, groupjoined by normal single bonds, and not coplanar with the other six 117 (7).It has been shown that the acetylene and carbonyl groups in the<-I IL’‘I,c dO (7)l12N.C. Baenziger, J. R. Doyle, and C. Carpenter, Acta Cryst., 1961, 14, 303.113B. Dickens and W. N. Lipscomb, J.Amer. Chem. SOC., 1961, 83, 489.114 0. S. Mills and G. Robinson, Proc. Chem. Soc., 1960, 421.115A. R. Luxmoore and M. R. Truter, Proc. Chem. SOC., 1961, 466.116 P. Corradini and G. Allegra, Atti Accad. naz. LGncei, Rend. Classe 8ci.Jis. mat. nat.,1959, 26, 511; 0. V. Starovskii and Y . T. Struchkov, Doklady Akad. Nauk S.S.S.R.,1960, 135, 620; R. Schneider and E. 0. Fischer, Naturwiss., 1961, 48, 452.117 J. D. Dunitz and P. Pauling, Helv. Chirn. Acta, 1960, 43, 2188OWSTON : INORGANIC STRUCTURES 465complex [ (C,H,)(MeC=-CMe),(CO)Co] have in fact combined to form tetra-methylcyclopentadienone, and the complex is thus a " sandwich " com-pound, (C,H,)Co(C5Me,0) ; this is unusual in having the two five-memberedrings in the " eclipsed " configuration.l18 Full details of the compoundFe,H,(CO),(MeCrCMe) in which the ligands had also combined to form(HOC*CMe:CMe*COH)Fe(CO)3-Fe(C0)3 have now been reported.llg In thecompound Rh,(CO),Cl, (Figure, p.110) the central (Rh,Cl,) bridge is notplanar, and the orbitals involved in the Rh-Rh metal-metal bond arethus at an unusual angle to each other;120 no theoretical reason for thisconfiguration is apparent.In acetylacetonylbipyridyltrimethylplatinum(~v) 121 the platinum atomis 6-co-ordinated to the three methyl groups, the two nitrogen atoms,and the active methylene carbon of the acetylacetonyl group (Fig. 20,p. 119); the two oxygen atoms, which normally co-ordinate to metals inacetylacetonyl complexes, are not involved in co-ordination at all.The compound Me,SnO*C,Cl,*OSnMe, has the trans-configuration, witha C-O-Sn angle of 127 O ; the plane containing the tin and oxygen atoms isperpendicular to the plane of the benzene ring.122Co-ordination Compounds.-Unwual co-ordination numbers.In diazo-aminobenzenecopper 123 the cuprous atoms are each approximately linearlyco-ordinated to two nitrogen atoms, a co-ordination type not previouslyrecorded for copper (8); the Cu-Cu distance (2.45 8) is very short but thisis attributed to the steric effect of the rigid planar diazoaminobenzenegroups rather than to specific metal-metal interaction.Further examples of molecules with five-co-ordination round thecentral atom have been recorded. In bisacetylacetonato-oxovanadium thefour oxygen atoms of the chelate groups form the base of a square pyramidhaving d ( V - 0 ) = 1-97 with the vanadium near its centre of gravityand the vanadyl oxygen [d(V=O) = 1.56 A] at the apex.12, In bisacetyl-acetonatozinc hydrate and in tris-o-diphenylarsinophenylarsineplatinummonoiodide (9) 126 the more usual trigonal bipyramidal arrangement isfound; this configuration has not previously been found in platinum com-pounds.An arrangement intermediate between the two types is reported11° A. A. Hock and 0. S. Mills, Proc. Chem. Xoc., 1958, 233; Acta Cryst., 1961,14, 139.lao L. F. Dahl, C. Martell, and D. L. Wampler, J . Amer. Chem. SOC., 1961, 83, 1761.121 A. G. Swallow and M. R. Truter, Proc. Chem. SOC., 1961, 166.122P. J. Wheatley, J., 1961, 5027.la3 I.D. Brown and J. D. Dunitz, Acta Cryst., 1961, 14, 480.la4R. P. Dodge, D. H. Templeton, and A. Zalkin, J . Chem. Phys., 1961, 35, 55.125E. L. Lippert and M. R. Truter, J . , 1960, 4996.126 G. A. Mair, H. M. Powell, and L. M. Venanzi, Proc. Chem. Soc., 1961, 170.L. F. Dahl and D. L. Smith, J . Amer. Chent. SOC., 1961, 83, 752466 CRYSTALLOGRAPHYin (Me,Asf CH,],-AsMe*[ CH,],*AsMe,)NiBr, where the nickel is surroundedby three arsenic and two bromine atorns.l27Eight-fold co-ordination usually occurs round heavy metals, but hasnow been found in a titanium complex lZ8 (10) in which the atoms roundthe titanium haveoriginally found inapproximately- the bis-&sphenoidal symmetry 32m[MO(CN),]~-.~~~ The same configuration has been- (lo)found in the zirconium tetraoxalate ion I3O and in tetrakisdibenzoyl-methanecerium,131 whereas in tetrakisacetylacetonato-thorium and -zirc-onium (and probably in the corresponding cerium compound) the oxygenatoms are a t the corners of an Archimedean antiprism (11).Thecharacteristic eight-fold co-ordination of uranyl complexes has been shownagain in uranyl nitrate hexahydrate where there are six oxygen atomscoplanar with the metal atom, and one above and one below this plane (12).The same arrangement is found in the corresponding triethyl phosphatecomplex (UO,)[ OP(OEt)3]2(N03)2,134 but in the ion [ (U02)2(S04)3]nzn -l theuranyl group is surrounded by only five oxygen atoms in EL nearly planepentagon. 135Few simple compoundsare known in which molecular oxygen is co-ordinated to a metal atom,though the importance of metal-porphyrin complexes as biological oxygen-carriers is well recognised.The structure of the ion [ (NH,),Co*O,*Co(NH3)]5+(13) has now been briefly reported;f36 the oxygen molecule is symmetricallybound to both metal atoms by bonds which are similar, a t first sight, tothose in n-type complexes between olefins and metals.Full details of the structure of bisacetylacetonatonickel, in which thenickel atom achieves octahedral co-ordination by forming trimeric mole-cules, have now been p~b1ished.l~'127 G. A. Mair, H. M. Powell, and D. E. Hem, Proc. Chem. SOC., 1960, 415.128 R. J. H. Clark, J. Lewis, R. 8. Nyholm, P. Pauling, and G. B. Robertson, Nature,129 J. L. Hoard and H.H. Nordsieck, J . Amer. Chem. SOC., 1939, 61, 2853.130 J. L. Hoard, G. L. Glen, and J. V. Silverton, J . Arner. Chem. SOC., 1961,83,4293.l3lL. Wolf and H. Biirnighausen, Acta C y s t . , 1960, 13, 778.132 D. Grdeni6 and B. Matkovi6, Acta Cryst., 1959, 12, 817.J. E. Fleming and H. Lynton, Chem. and Id., 1960, 1416.134 J. E. Fleming and K. Lynton, Chem. and Id., 1960, 1415.136 M. Ross and H. T. Evans, J . Inorg. Nuclear Chem., 1960, 15, 338.136C. Brosset and N.-G. Vannerberg, Nature, 1961, 190, 714.137G. J. Bullen, R. Mason, and P. Pauling, Nature, 1961, 189, 291.Metal complexes with discrete molecules or ions.1961, 192, 222OWSTON : INORGANIC STRUCTURES 467Several complexes of cupric copper have been studied, the most unusualbeing the salt [Cr(NH,),][CuCl,] in which the positive ion is octahedraland the negative ion is trigonal bipyramidal with d(Cu-C1) = 2.35 A forthe equatorial and 2.32 A for the polar Copper shows no ten-dency to form n-type complexes with ligands containing N-N, e.g., benzene-azo-2-naphthol is co-ordinated to copper by one nitrogen and one oxygenatom (14) 139 and the dithizonate ion uses only one of its four nitrogenatoms and a sulphur atom;140 in each case two molecules of the ligandcombine with the copper atom to form a square-planar complex (15).The other cupric complexes are more predictable in stereochemistry, form-ing square-planar complexes, with two more distant atoms from othermolecules completing a distorted octahedron round the metal.In twocases these two atoms are of copper, with a Cu-Cu distance of 3.3 A in ifrsalicylaldehyde-methylimine complex 141 and 2.7 A (a distance shortenough to suggest metal-metal interaction) in the salicylaldehyde-ethylene-di-imine complex;142 it is interesting to note that in the correspondingiron complex 143 the Fe-Fe distance is longer (3.4 A).In the copper-biuret complex, K,[Cu(NH*CO*NH*CO*NH),],4H20, however, the octa-hedron is completed by two nitrogen atoms which are themselves alreadyco-ordinated to copper atoms; the Cu-N bond lengths are 1.93 within themolecule and 3-33 A between molecules.144 In the copper salt of glycine 145the octahedron consists of two nitrogen and four oxygen atoms.Cupric acetate crystallises from pyridine as a dimer, Cu,(AcO),(C,H,N),with an octahedral structure like that of the dihydrate.146 The metal-metal bond is 2.70 A long, slightly longer than in cupric acetate dihydratels8M.Mori, Y. Saito, and T. Watanabe, Bull. Chem. SOC. Japan, 1961, 34, 295.139 J. A. J. Jarvis, Acta Cryst., 1961, 14, 961.140R. F. Bryan and P. M. Knopf, Proc. Chem. SOC., 1961, 203.lalB. Meuthen and M. von Stackelberg, 2. anorg. Chem., 1960, 305, 279.14*K. Pachler and M. von Stackelberg, 2. anorg. Chem., 1960, 305, 286.143 C. Scheringer, K. Hinkler, and M. von Stackelberg, 2. anorg. Chem., 1960,306, 35.la4 H. C. Freeman, J. E. W. L. Smith, and J. C. Taylor, Acta Cryst., 1961, 14, 407.145K. Tomita and I. Nitta, Bull. Chem. Soc. Japan, 1961, 34, 286.146 F. Hank, D. SternpelovB, and K.HanicoviL, Chem. Zvesti, 1961, 15, 102468 CRYSTALLOGRAPHY(2.64 A). A different type of dimeric structure with copper-copper bonds3.00 A long has been found in the square-planar cupric complex shown inFig. 25 (p. 133); here again there is electron exchange between the metalatoms, leading to an abnormally low magnetic moment in the s01id.l~~One of the copper atoms also has a fifth oxygen neighbour in an apicalposition, with Cu-0 = 2.68 8.The structures of bisdimethylglyoximinodiamminecobalt nitrate,148and the nickel Lifschitz complex ion,(Ni[PhCH(NH,)*CH(NH,)Ph],(H,O), )2+,149 in which the metal atoms areoctahedrally co-ordinated, call for no special comment.Most metal-nitrosyl complexes have linear metal-N-0 bonds, but thoseof ruthenium have been a notable exception.150 In K,[RuCl,,NO], how-ever, the bond is linear ;151 in (NH4),[RuC1,(OH)NO], where the rutheniumhas the same valency, the Ru-N-0 angle is 1530.15, The correspondingaquo-complex, K,[RuCl,,H,O], has also been studied.153U701f-ram’s red salt 154 consists of chains of alter-nate PtIl(EtNH,), and PtIV(EtNH2), groupswith a chlorine atom between each pair, butthe distribution of the two kinds of group ’ ’ N 1 ‘N .is random.The idealised structure is shownin (16). A similar random arrangement of PtBr,( H,N-CH,*CH,*NH,)groups linked by bromine atoms is found in [(C,H8N,)PtBr3],.155 In eachcase the optical properties of the crystal indicate that there is ready charge-transfer along the chains.Halides.-The majority of metal halide complexes conform to one of therecognised structure types, and crystallographic work is often directed toan understanding of their physical properties (e.g., ferroelectricity andmagnetism) rather than of their chemistry.The complexes KMF, (M = Mn,Fe, Co, Ni, and Zn) have been studied, and all have the symmetrical perovs-kite structure at room temperature, each metal atom being surroundedby an octahedron of fluoride ions. Potassium trifluoro-chromate and-cuprate are less symmetrical, however, indicating a Jahn-Teller distor-tion of the CrF, and CuF, octahedra associated with the egl and eg3electron configurations. Potassium trifluoro-manganate, -ferrate, and-cobaltate form less symmetrical structures at temperatures below theirNee1 p0ints.4~3 156Two disordered structures of unusual type have been reported.NN i t ” tu/” 14 /” N-----~%-P\-c\--- pt---- I 6)l 4 7 G.A. Barclay, C. M. Harris, B. F. Hoskins, and E. Kokot, Proc. Chem. Soc.148K. S. Viswanathan and N. R. Kunchur, Acta Cryst., 1961, 14, 675.149 S. C. Nyburg, J. S. Wood, and W. C. E. Higginson, Proc. Chem. SOC., 1961,150 J. Lewis, Sci. Progr., 1959, 47, 506.151T. 8. Khodashova and G. R. Bokii, Zhur. Strukt. Khim., 1960, 1, 151.152 N. A. Parpiev and M. A. Porai-Koshits, KristaZZogra$ya, 1959, 4, 30.153 T. S. Khodashova, Zhw. Strukt. Khim., 1960, 1, 333.154 R. M. Craven and D. Hall, Acta Cryst., 1961, 14, 475.155 T. D. Ryan and R. E. Rundle, J . Amer. Chem. SOC., 1961, 83, 2814.1560. Beckman and K.Knox, Phys. Rev., 1961, 121, 376; A. Okazaki and Y.1961, 264.297.Suemone, J . Phys. SOC. Japan, 1961, 16, 176, 671OWSTON : INORGANIC STRUCTURES 469The Jahn-Teller effect is shown more clearly in the structure of anhy-drous chromous chloride, reported this year by no less than five groups of~0rkers.l~‘ The chromium atom is surrounded by four coplanar chlorineatoms, d(Cr-C1) = 2-39, or 2.37, 8, with two others above and below thisplane, d(Cr-C1) = 2.91 8, completing an elongated octahedron.The bond lengths of the [CuC1,I2- ion in diczesium tetrachlorocupratehave been refined 158 and the departure of the ion from regular tetrahedralsymmetry has been confirmed. This distortion, which is also due to theJahn-Teller effect is still more marked in the corresponding tetrabromo-compound.The structures of Nb,Cl, ( C d l , - t y ~ e ) , l ~ ~ of TiBr, (also CdI,-type),lG0of the polymorphic forms of K,VF,, Rb,VF,, and Cs2VF, (K$!hF, andK,GeF, types),161 NaMoF, (which is like NaSbF,),162 and K,TiCl, (likeK2PtC1,) 163 have been found.GaF3,3H,O consists l6* of separate octa-hedra of [ Ga(H,O),] and [ GaF,], thus resembling a-A1F3,3H,O.The cuprous isocyanide complex Cu1,MeNC consists of infinite chains of(CuI,), with Cu(CNMe), side-chains. The cuprous atoms are tetrahedrallyco-ordinated (17) throughout~l65Stannous chloride dihydrate consists of layers of pyramidal (SnCl,,H,O)groups, which can be regarded as approximately tetrahedral with a lonepair of electrons at the apex, held together by hydrogen bonds from theremaining water molecules.166 The (SnC1,)- ion is also pyramidal inK,SnCl,,H,O, which is better written as KC1,KSnCl3,H20.167Anhydrous stannous chloride has a less regular structure 168 in whichthe tin atom has nine chlorine atoms as nearest neighbours with Sn-C1 = 2.66-3.86 8; the arrangement is best regarded as a very distorted version of157 J.W. Tracy, N. W. Gregory, E. C. Lingafelter, J. D. Dunitz, H.-C. Mez, R. E.Rundle, C. Scheringer, H. L. Yakel, and M. K. Wilkinson, Acta Cryst., 1961, 14, 927;H. R. Oswald, Helv. Chim. Acta, 1961, 44, 1049.158 B. Morosin and E. C. Lingafelter, J . Phys. Chem., 1961, 65, 50; Acta Cryst., 1960,13, 807.159 H.-G. v. Schnering, H. Wohrle, and H. Schiifer, Naturwiss., 1961, 48, 159.lG0 P.Ehrlich, W. Gutsche, and H.-J. Seifert, 2. anorg. Chem., 1981, 312, 80.la2A. J. Edwards and R. D. Peacock, J . , 1961, 4253.163 J. A. Bland and S. N. Flengas, Canud. J . Phys., 1961, 39, 941.ls41. Maak, P. Eckerlin, and A. Rabenau, Naturwiss., 1961, 48, 218.la5P. J. Fisher, N. E. Taylor, and M. M. Harding, J., 1960, 2303.la6B. Kamenar and D. Grdenid, J . , 1961, 3954.167D. Grdeni6 and B. Kamenar, Proc. Chem. SOC., 1961, 304.168 J. M. van den Berg, Acta Cryst., 1961, 14, 1009.W. Liebe, E. Weise, and W. Klemm, 2. anorg. Chem., 1961, 311, 281470 CRYSTALLOGRAPHYthe nine-fold configuration of (2). Anhydrous zinc chloride crystallises inthree different modifications, two of them being new structure types, andthe third being like mercuric chloride; in all three the zinc atom is tetra-hedrally surrounded by four chlorine atoms with Zn-C1 = 2.34, 2-31, and2.27 8 in the a-, p-, and y-modificafion~.~~~Octahedral co-ordination of both metals is found in SrPb21,,7H20,where (PbI,) octahedra are joined by corners to form a three-dimensionalnetwork, six water molecules are associated with the strontium ion, andone is zeolitic; the Pb-I distances of 3.20 and 3-14 8 suggest some covalentcharacter.170A detailed theoretical study has been made of the crystal forces whichcan distort the I,- ion from its ideally linear form.171A full study of Hg,O,NaI has been made by both X-rays and neutrons;the structure consists of square pyramids, Hg0213, linked by sharing basaledges to form corrugated chains, and the triangular faces of the pyramidsare linked to form chains of Archimedean antiprisms, NaI,O,, surroundingthe sodium ions and perpendicular to the pyramid chains.172Hydroxides and Hydrates.-A new structure has been found for potas-sium hydroxide, consisting of infinite zig-zag chains of hydroxyl ionslinked by other long hydroxyl bonds (O-H--O = 3.35 8); the potassiumions lie between two chains, with six oxygen atoms as nearest neighboursin an approximately octahedral configuration. 173 The structure of lithiummethoxide is unusual.17* It consists of layers of lithium atoms in a squarearray, with a methoxyl group lying alternately above and below the centreof each square of four lithium atoms; the co-ordination round the oxygenatoms is thus square pyramidal (4 lithium atoms at 1-95 A and one methylgroup at 1.42 A), and round each lithium atom there is a distorted tetra-hedron of oxygen atoms.I n cupric hydroxide 175 the copper atoms are linked by hydroxylgroups to give infinite chains.These chains are packed to bring oxygenatoms from other chains above and below the copper atoms, each ofwhich thus has four oxygen atoms from its own chain [d(Cu-0) = 1.93 81and two from other chains [d(Cu-0) = 2.63 81 in an elongated octahedron.The copper-copper distance is 2.95 8. The mineral stottite, FeGe(OH),,has octahedra of hydroxyl ions round both iron and germanium atoms;176the octahedra are linked into a three-dimensional structure by sharingcorners, and the average bond lengths are d(Ge-OH) = 1.96 A andd(Fe-OH) = 2-14 8.An unusual, irregular eight-fold co-ordination occurs 17' in GdCI3,6H2O ;the gadolinium atom is co-ordinated to two chlorine atoms and six watermolecules, these groups being linked by hydrogen bonds to separate .160 B.Brehler, 2. Krist., 1961, 115, 373.17oA. Ferrari, A. Braibanti, and A. M. Lanfredi, Acta Cryst., 1961, 14, 489.171R. E. Rundle, Acta Cryst., 1961, 14, 585.172K. Aurivillius, Acta Chem. Scand., 1960, 14, 2196.1 7 3 J. A. Ibers, J. Kumamoto, and R. G. Snyder, J . Chem. Phys., 1960, 33, 1164.1 7 4 P . J. Wheatley, J., 1960, 4270.175 H. Jaggi and H. R. Oswald, Actu Cryst., 1961, 14, 1041.176H. Strunz and M. Giglio, Actu Cryst., 1961, 14, 205.1 7 7 M. Marezio, H.A. Plettinger, and W. H. Zachariasen, Acta Cryst., 1961, 14, 234SUTOR: ORGANIC STRUCTURES 47 1chloride ions. andd(Gd-H,O) = 2.39-2.42 &- 0.02 8. Zinc hydroxide chloride hydrate,Zn,( OH) 8C1,,H20, has a more normal stereochemistry, and can be regardedas being derived from zinc hydroxide. It has a layer structure, and ineach layer 60% of the zinc atoms are surrounded by an octahedron ofhydroxyl groups [d(Zn-0) = 2.17 81 and 40% by a tetrahedron of threehydroxyl groups and one chlorine atom ; these co-ordination groups arelinked into layers by sharing hydroxyl groups, and the layers are joinedby hydrogen- bonded water molecules, and by OH43 hydrogen bonds.178The bond lengths are d(Gd-C1) = 2.768 & 0408P. G . 0.3. ORGANIC STRUCTURESCarboxyli~ Acids and Related Compounds.-There are two classes of acidsalts MHX, of monocarboxylic acids HX.In one, the two acid radicalsare equivalent and joined by a hydrogen bond which is crystallographicallysymmetrical. In the other, the two radicals are nonequivalent and dis-tinguishable in the crystal structure. Sodium hydrogen diacetate, whosecomplete structure analysis is now reported,179 is an example of the firstkind. The two acetate residues are related by a two-fold axis across whichthey are linked by a hydrogen bond with d(0-H-0) = 2.44 & 0.01 8.Another example is rubidium hydrogen di-o-nitrobenzoate with d(0-H-0)= 2.43 & 0.06 di, but potassium hydrogen di-p-nitrobenzoate belongs to thesecond group la0 and has a short unsymmetrical hydrogen bond of 2.49 &0 - 0 2 k In the latter compound, the anion X- makes contacts with apotassium ion through the two oxygen atoms of the carboxyl group andone oxygen of the nitro-group, but the neutral molecule HX makes onlyone contact through a carboxyl oxygen at0l.h.Potassium hydrogen male-ate 54 was discussed in an earlier section.The crystal structure of anhydrous copper(I1) formate consists of a three-dimensional array of copper atoms joined by formate groups in an anti-synbridging arrangement.lsl Each copper atom has a distorted tetragonalpyramidal co-ordination of four oxygen atoms in the same plane as thecopper atom [d(Cu-0) = 1.95 81 and a fifth oxygen atom [d(Cu-0) = 2-40A]a t 31 O to the normal to this plane. The crystal structure of sodium pyruvateis described lS2 and there is a refinement of that of nonanoic acidhydrazide.ls3 Molecules of oxalyl bromide 184 lie in non-planar sheets inwhich each molecule is linked to four neighbours by charge-transfer bondswith d(Br-0) = 3.27 8.In o-chlorobenzoic acid,lS5 molecular overcrowding is relieved by a twistW.Nowacki and J. N. Silverman, 2. Krist., 1961, 115, 21.179 J. C. Speakman and H. H. Mills, J . , 1961, 1164.leoH. N. Shrivastava and J. C. Speakman, J . , 1961, 1151.ls1G. A. Barclay and C. H. L. Kennard, J., 1961, 3289.lE2 S. S. Tavale, L. M. Pant, and A. B. Biswas, Acta Cryst., 1961, 14, 1281.lEsL. H. Jensen and E. C. Lingafelter, Acta Cry&, 1961, 14, 507.184 P. Groth and 0. Hassel, Proc. Chem.SOC., 1961, 343.la5G. Ferguson and G. A. Sim, Acta Crgst., 1961, 14, 1262472 CRYSTALLOGRAPHY(13") of the carboxyl group out of the aromatic plane and a sideways andout-of-plane displacement of the exocyclic carbon and chlorine atoms awayfrom each other. An unusual feature of the crystal structure of melliticacid,la6 C,(C02H)6, is the non-planarity of hydrogen-bonded carboxylgroups. The angles between the normals to the planes of hydrogen-bondedpairs vary from 4" to 37". The structure contains two crystallographicallyindependent sets of molecules which differ mainly in the tilts of the carboxyigroups to the benzene ring. In tetramethylenedi(ammonium adipate),la7the carboxyl groups are inclined at 66" to the carbon chain as comparedwith 6" in adipic acid.The cation in ethylenedi(amm0nium sulphate) 188 is in the gauche formwith an azimuthal angle of 75.7" between the two halves of the molecule.Accurately determined bond lengths in 2-aminoethanol phosphate are allnormal.lsg In the crystal structure and that of p-aminobenzenearsonicacid,lgO the three hydrogen bonds formed by the nitrogen atom suggest thatmolecules have the zwitterion form.Acyclic Molecules.-The molecular dimensions of 1,2-dichloroethane at-140" have been redetermined lgl because of a computational error in theprevious work. The new bond lengths are d(C-Cl) = 1.80 &- 0.02 A andd(C-C) = 1.55 & 0.03 8.2-Bromo-2,3,3-trimethylbutane lg2 belongs tothe cubic system and has a statistically disordered arrangement of mole-cules.A careful t'hree-dimensional analysis of the hydrogen cyanide tetramer 93has confirmed the diaminomaleinitrile structure (NiCCNH,:),.Bondlengths are d(C=C) = 1.363, d(C-C) = 1.434, 1.441, d(C-N) = 1.398, 1.387,and d ( C 3 ) = 1.164, 1-166, all &0.003A. The molecule has no mirrorplane. It is twisted by 6" about the central C=C bond, and one amino-group is tetrahedral and the other planar. Both groups form N-He-Nhydrogen bonds. In cyanamide,lg4 d ( H ) = 1.15 A and the N - C a groupis linear.An electron-diffraction study of the high-temperature phase of thioureais reported,60 and the crystal structure of tetramethylthiourea has beendetermined. lg5 The results of a neutron-diffraction refinement of thecrystal structure of dimethylglyoxime 196 differ from the X-ray ones.Inparticular, there is a difference of 0-08 A between the two C-C single bonds.Molecules are linked by a normal O-H-N hydrogen bond, rather than by azwitterionic one, as has been suggested, with L(0-H-N) = 140" & 3",significantly different from the assumed linear arrangement. In the trans-186S. F. Darlow, Acta Cryst., 1961, 14, 159.1 8 7 S. Hirokawa and T. Ashida, Acta Cryst., 1961, 14, 1004.K. Sakurai, J . Phys. SOC. Japan, 1961, 16, 1205.J. Kraut, Acta Cryst.. 1961, 14, 1146.lsoA. Shimada, Bull. Chem. SOC. Japan, 1961, 34, 639.lS1 W. N. Lipscomb, F. E. Wang, W. R. May, and E. L. Lippert, Acta Cryst., 1961,1QaT. Koide, Y. Kato, and T. Oda, Bull. Chem. SOC. Japan, 1960, 33, 1572.193B.R. Penfold and W. N. Lipscomb, Acta C~yst., 1961, 14, 589.194Z. V. Zvonkova and A. K. Khvatkina, Kristallograjiya, 1961, 6, 184.195 Z. V. Zvonkova, L. I. Astakhova, and V. P. Glushkova, Kristallografiya, 1960,196 W. C. Hamilton, Acta Cryst., 1961, 14, 95.14, 1100.5, 547SUTOR: ORGANIC STRUCTURES 473dimer of nitrosoisobutane 197 (Me,CH*CH,*NO*),, the central C*NO*NO*Cgroup is planar and the bond lengths, d(N-N) = 1-27 and d(N-0) = 1.30,both &0.02B, are intermediate between the values for single and doublebonds. The azo-bond in azodicarboxamide (NH2*CO*N:), has d(N-N)= 1-24 & 0.03 A as in azobenzene, and the adjacent single C-N bond is1.48 & 0.02 A.In N - et hyl-2,2'- dimet h y lsulp hon ylvinylideneamine , ( MeSO, ) ,W-NE t ,the C=C=N group is nearly linear: L(GC-N) = 173" & lo, and ,/(C-N-C)= 144.5" & lo, in contrast to the completely linear arrangement of thesefour atoms found in two methylvinylideneamines.199 In di-p-tolyl di-sulphide,200 there is an angle of 104" between the two planes of the molecule,and the dimensions of the disulphide bridge are d(S-S) = 2.06 A andL(C-S-S) = 106.5".An X-ray analysis of tetraethyldiphosphine di-sulphide Et4P2S, has shown that the length of the P-P bond (2.22 & 0.01 h)is not significantly different from this bond in inorganic phosphorus com-pounds.201 Other bond lengths are d(P=S) = 1.94 & 0.01 A correspondingto a pure double bond and d(P-C) = 1.83 & 0-02 8.Aromatic and Other Cyclic Compounds.-A careful study of biphenyl ,02from three-dimensional data collected by counter methods has provedconclusively that the molecule is centrosymmetric and not twisted as inthe vapour phase.Hence a statistical disordering of non-centred moleculesin space-group P2,/c is ruled out. There is no indication of significant dis-placements of the ortho-hydrogen atoms from a planar trigonal arrangement.This is in contrast to the small in-plane displacements of these atoms, takenas indicative of steric strain, and found in a less accurate two-dimensionalstudy carried out simultaneously. ,03 4,4'-Dinitrobiphenyl was thought tobe an example of a centrosymmetric molecule crystallising in a non-centro-symmetric space-group Pc. A new study of the compound ,04 has, how-ever, shown that the molecules are non-centrosymmetric, with the benzenerings and nitro-groups twisted in a helical fashion about the long axis ofthe molecule.On the other hand, 4,4'-dihydroxybiphenyl SO5 crystallisesin the centrosymmetric space-group P2,/a and appears to be planar.Molecules of trans-orp-dicyanostilbene are non-planar.206 Adjacent C-CENand benzene groups are rotated away from each other out of the plane ofthe four central carbon atoms.The results of a three-dimensional refinement of the crystal structureof 4-nitroaniline ,07 show that the nitro- and amino-groups are twisted,19" and 16" respectively, out of the plane of the aromatic ring. There isapparently a small but significant contribut*ion by the quinonoid resonanceOther values support a urea-type re~0nance.l~~H.Dietrich and D. C. Hodgkin, J . , 1961, 3686.J. H. Bryden, Acta Cryst., 1961, 14, 61.Ins J. J. Daly, J . , 1961, 2801.200L. G. Vorontsova, Z. V. Zvonkova, and G. S. Zhdanov, Kristallogrufiya, 1960,201 S. N. Dutta and M. M. Woolfson, Acta Cryst., 1961, 14, 178.202 G. B. Robertson, Nature, 1961, 191, 593.203 J. Trotter, Acta Cryst., 1961, 14, 1135.204 J. N. van Niekerk and E. G. Boonstra, Actu Cryst., 1961, 14, 1186.206 M. S. Farag and N. A. Kader, J . Chem. U.A.R., 1960, 3, 1.206 S. C. Wallwork, Acta Cryst., 1961, 14, 375.5, 698.K. N. Trueblood, E. Goldish, and' J. Donohue, Acta Cryst., 1961, 14, 1009474 CRYSTALLOGRAPHYform to the structure of the molecule. In both l-chloro- and l-bromo-2,4-dinitrobenzene,208 the nitro-groups are tilted out of the plane of the benzenering, the 4-nitro-groups by 15", and the 2-nitro-groups by about 40".Sterichindrance has also caused in-plane displacements of the halogen atom awayfrom the adjacent 2-nitro-group. The crystal structure of m-dinitrobenzenehas been refined by using new three-dimensional data,209 but chemicallyequivalent bonds still differ considerably though possibly not significantly,e.g., d(C-C) = 1.34 and 1-41 8.Direct evidence of the nature of the stereoisomerism and the configura-tion of the two forms of 2-chloro-p-benzoquinone 4-oxime acetate (18) hasCIo<- form /3 - form(18)been obtained from their crystal structures.210 In the a-form, the chlorineatom is syn, and in the ,&form it is anti with respect to the oxime acetategroup.Bond lengths and angles are consistent with a quinonoid ring inboth cases. In 5-chlorosalicylaldoxime,211 the oxime group is rotated aboutthe C-C bond out of the plane of the benzene ring. Molecules of tetrachloro-1,4-bistriethylstannyloxybenzene (19) z12 adopt the truns-form withd(Sn-0) = 2.08 & 0.06 A. The crystal struc-'I .SnEt, tures of chloranil 213 and 2,3-dichloro-1,4-naphthaquinone 214 are reported. In theformer, cohesive forces between molecules arise Et3Sn CI CI mainly from dipole interaction of C=O bonds.2-Naphthoic acid is planar, in contrast to l-naphthoic acid where over-crowding in a planar model causes an 11" twist of the carboxyl group out ofthe molecular plane.215 9-Bromo-lO-chloroanthracene 216 and 9-bromo- 10-methylanthracene 217 are examples of statistically disordered molecules.Pyracene (20) 218 and 20-methylcholanthrene (21) 219 are planar. As in0 0 0"'0' I 9 )~~208 K. J. Watson, Nature, 1960, 188, 1102.SO9 J. Trotter, Canad. J . Chtem., 1961, 39, 1638.21O E. Fischmann, C. H. MacGillavry, and C. Romers, Acta Cryst., 1961,14,753, 759.211 S. H. Simonsen, C. E. Pfluger, and C. M. Thompson, Acta Cryst., 1961, 14, 269.212P. J. Wheatley, J . , 1961, 5027.213 I. Ueda, J . Phys. SOC. Japan, 1961, 16, 1185.214 J.-C. Mhtras, Acta Cryst., 1961, 14, 153.216 J. Trotter, Actu Cryst., 1961, 14, 101.216 M. Hospital, Acta Cryst., 1961, 14, 76.217 M.-T. Prat, Acta Cryst., 1961, 14, 110.21sG.L. Simmons and E. C. Lingafelter, Acta Cryst., 1961, 14, 872.21Q J. Iball and S. G. G. MacDonald, 2. Krist., 1960, 114, 439SUTOR: ORGANIC STRUCTURES 475acenaphthene,220 the bonds between the niethylene carbon atoms (1.59 &0.03, 1.55 -+ 0.01 8, respectively) are not significantly longer than usual.Both tetracene 221 and pentacene 222 are planar with symmetry mmrn withinthe limits of the experimental measurements. The general arrangement ofmolecules in the crystal structures is similar to that in the lower members ofthe series, naphthalene and anthracene, but the crystal system has changedfrom monoclinic to triclinic, leading to a closer packing of the mole-cules. The two coronene derivatives 1,2 : 7,8-dibenzocoronene and1,12 : 2,3 : 4,5 : 6,7 : 8,9 : 10,ll-hexabenzocoronene are also planar.223 Inthe former, the bond lengths are similar to corresponding ones in perylene.In dimethylfulvene (22) the five-membered ring and attached carbonatom are coplanar, and it is doubtful whether the deviations (0.04 8) ofthe methyl carbon atoms from this plane are significant.224 The chlorineCI CI CI CI D==a CI CI Ci C1 (23)atoms are all displaced from the planes of the five-membered rings in per-chlor~fulvalene~~~ (23).The central C=C bond is as long as 1-49 A andthe two halves of the molecule are twisted 41" about this bond to relievesteric strain even more. The structure of the sodium salt of tropolone hasbeen further refined.226 Z-Phenyla~ulene~22~ like azulene, has a disorderedcrystal structure in which there is a random reversal of the direction of thelong molecular axis.Heterocyclic Compomds.-In the crystal structure of the cancer chemo-therapeutic agent meso- 174-diaziridin- 1 '-ylbutane-2,3-diol (24) , there arehydrogen bonds between the hydroxyl groups and nitrogen atoms of theaziridine ring with d(0-H-N) = 2-87 & 0.01 8.As in other moleculeshaving three-membered rings, the C-C distance of 1.46 A is less than theusual value. 228 A three-dimensional refinement of succinimide 229 has pro-duced some changes in bond lengths, and average molecular dimensions ared(C-C) = 1.505, 1.506, d(C-N) = 1.385, and d(C-0) = 1.227, all &O-Oll 8.Only one of the oxygen atoms is involved in hydrogen-bond formation,[d(N-H-O) = 2-87 A].A similar arrangement has been observed in220Ann. Reports, 1958, 55, 458.231 J. M. Robertson, V. C. Sinclair, and J. Trotter, Acta Cr,ust., 1961, 14, 697.823 R. B. Campbell, J. M. Robertson, and J. Trotter, Acta Cryst., 1961, 14, 705.*23 J. M. Robertson and J. Trotter, J . , 1961, 1115, 1280.2z4N. Norman and B. Post, Acta Cryst., 1961, 14, 503.*Zs P. J. Wheatley, J., 1961, 4936.228 R. Shiono, Acta Cryst., 1961, 14, 42.2 2 7 B . D. Sharma and J. Donohue, Nature, 1961, 192, 863.22*E. S. Gould and R. A. Pasternak, J . Amer. Chem. SOC., 1961, 83, 2658.2esR. Mason, Acia Cryst., 1961, 14, 720476 CRYSTALLOGRAPHYN-chlorosuccinimide 230 where a short intermolecular approach [&(Cl-O)= 2.8881 between one oxygen atom and the chlorine atom is possibly indi-cative of electrostatic attraction. Molecules of a-ethyl-d-iodo-a-phenyl-glutarimide 231 and the hydrobromide of ethyl 1 -methyl-4-phenylpiperid-ine-4-carboxylate 232 are also hydrogen-bonded in their crystal structureswith d(N-He-0) = 2.85 and d(N-He-Br) = 3.24 8, respectively.The molecular structure of 2,2'-pyridil (25) is entirely covalent and notmes0ionic.2~3 The molecule lies in two planes, each containing a pyridinering, carboxyl group, and the adjacent carbon atom, and inclined to eachH ti(26) (27)other at 83".According to an X-ray analysis of l-benzyl-1,4-dihydro-nicotinamide (26), the dihydronicotine ring is planar, with the benzene andamide groups rotated 83" and 4" respectively out of this plane.18 Thebond lengths in the ring are d(C=C) = 1.32, d(C-C) = 1.51, 1.53, andd(C-N) = 1-43, 1.38, all &O.Ol 8.There are two reports of the crystalstructure of pyridine N-oxide hydrochloride. 234 Molecules of N-hydroxy-phenazine are statistically arranged about two possible 180 " orientationsin the crystal structure.235 The N-0 distance is 1-24 &- 0.02 A, and 1.27 Ain 5,10-dihydroxyphenazine.236 Results in a preliminary report of thecrystal structure of N-p- bromophenylsydnone are in agreement with themesoionic aromatic character of the sydnone system (27). The phenyl andsydnone rings are planar but twisted about the C-N axis relative to eachother.The bond lengthsin barbituric acid dihydrate 238 indicate the triketo-form of the molecule,with mm symmetry.Water molecules are hydrogen-bonded in pairs andtheir hydrogen-bond co-ordination differs from the usual tetrahedral one inthat it is planar and approximately trigonal. Despite the compact packingof molecules, the arrangement does not appear to be stable since the crystalseffloresce in a few days. A full account of the X-ray analysis of calciumthymidylate has now appeared.239 The deoxyribose ring adopts the usualpuckered form and makes an angle of 75" with the plane of the thyminegroup. The conformation of the thymidylate ion about the glycosidic linkSeveral pyrimidines and purines have been studied.230R. N. Brown, Acia Cryst., 1961, 14, 711.231M. Bonamico, F. Coppola, and G. Giacomello, Gazzettcc, 1961, 91, 193.232 M. Brufani, D. Duanti, G.Giacomello, and L. Zambonelli, Gazzetta, 1961, 91, 754.233 S. Hirokawa and T. Ashida, Acta Cryst., 1961, 14, 774.234 Y. Namba, T. Oda, H. Ito, and T. Watanabe, Bull. Chem. SOC. Japan, 19e0, 33,1618; G. Tsoucaris, Acta Cryst., 1961, 14, 914.235R. Curti, V. Riganti, and S. Locchi, Acta Cryst., 1961, 14, 133.236V. Riganti, R. Curti, and A. Coda, Ricerca Bci., 1960, 30, 1570.237H. Bilmighausen, F. Jellinek, and A. Vos, Proc. Chern. ~Coc., 1961, 120.23sG. A. Jeffrey, S. Ghose, and J. 0. Warwicker, Acta Cryst., 1961, 14, 881.239K. N. Trueblood, P. Horn, and V. Luzzati, Acta Cr?yst., 1961, 14, 965SUTOR: ORGANIC STRUCTURES 477is shown to be intermediate between that in the DNA model of Crick andWatson and that suggested by Wilkins and his colleagues. In the hydro-bromides of 9-methyladenine and 1 -methylcytosine,240 there are no hydrogenbonds directly joining the bases.Instead each molecule forms threehydrogen bonds with neighbouring bromide ions. I n the adenine molecule,access to the remaining acceptor nitrogen atom appears to be hindered bythe 9-methyl group and a similar effect probably exists in pol&pucleotidestructures.The tetragonal phase of cyc1(3,2,2)azine (28) consists of molecules whichare either rotating freely or randomly oriented in their respective planes.241,s-c=oN - CH2Me Me(28) ( 2 9 ) ( 30)This is probably also true of the monoclinic phase. However, l,4-dibromo-cyc1(3,2,2)azine has an ordered crystal structure.242 Each half moleculein indirubin is planar,2*3 and the whole molecule is stabilised in thetrans-form by two intramolecular contacts with d(N-Ha-0) = 2.70 andIn the five-membered ring of 3-methyl-2-thiobenzothiazoline ( 29),244 theC-S bond lengths are 1-77 and 1-78 8.Similar values (1.79, 1.78, both-J=0-03 A) are found in 2-benzoylimino-3-methylthiazolid-5-one (30) whichhas been established as the compound obtained from acid-catalysed cyclisa-tion of the derivatives of N-benzoylthiocarbamoylsarcosine. 246Results of an X-ray study of the dimethylarninoborine trimer 246 showthat the chemical formula is (BH,),(NMe,),. Nitrogen and boron atomsform a " chair "-shaped ring of alternating BH, and NMe, groups withaverage dimensions d(B-N) = 1.59 & 0.02 8, L(B-N-B) = 113 &- 1 O , and,/(N-B-N) = 114 &- 2".A " chair "-shaped ring is also adopted by thearsenic atoms in arsenobenzene 247 which has been shown to be a hexamerL ! S ~ ( C ~ H , ) , and not a dimer as usually supposed. Average ring dimensionsare d(As-As) = 2.46 8 and ,/(As-As-As) = 91". Both octa(si1sesquioxan)and octa( methylsilsesquioxan) are cage-like molecules formed by linking sixsilicon-oxygen rings. 248Natural Products and Related Compounds.-The success of X-raymethods in elucidating the molecular structure of complex natural productsis obvious again this year. An X-ray analysis of epilimonol iodoacetate 249d(C-H-0) = 3.01 A.240R. F. Bryan and K. Tomita, Nature, 1961, 192, 812.241A. W. Hanson, Acta Cryst., 1961, 14, 365.2P2A. W. Hanson, Acta Cryst., 1961, 14, 124.243H. Pandraud, Acta Cryst., 1961, 14, 901.a44P.J. Wheatley, J . , 1961, 4379.245H. Steeple, Actu Cryst., 1961, 14, 847.246 L. M. Trefonas, F. S. Mathews, and W. N. Lipscomb, Acta Cryst., 1961, 14, 273.247 K. Hedberg, E. W. Hughes, and J. Waser, Acta C r p t . , 1961, 14, 369.248 K. Larsson, Arkiv Kemi, 1960, 16, 215, 203.240 S. Amott, A. W. Davie, J. M. Robertson, G. A. Sim, and D. G. Watson, J.,1961, 4183478 CRYSTALLOGRAPHYhas established limonin as a tetracyclic triterpenoid of the euphol typefrom which carbon atoms in the side chain have been removed and theremainder converted into a furan ring (31). An unusual feature of theMe I-\ / ow 00 :f i(3 1) (32)structure of gelsemicine, 250 whose molecular framework has one carbonatom less than that of gelsemine, is a methoxyl group linked to the oxindolenitrogen atom (32).The molecule has an intramolecular hydrogen bondbetween the C=O and NHMe groups. Thelepogine,25l clerodin,252 echitam-ine, 253 and macusine-A 254 have had their molecular configurations deter-mined by X-ray methods, while the structures of caracurine I1 255 andsuprasterol I1 256 have been solved simultaneously by X-ray and chemicalmethods. Complete details of the structure analyses of iso~lovene,~5~l y c o c t ~ n i n e , ~ ~ ~ and aconinone 259 are now available. A preliminary reportof the work on the bromo-dilactone from jacobine 260 shows that the lactonegroups C-(c--O)-O-C are planar and the bonds designated x are 0-1 Ashorter than those designated y.Two antibiotics have been investigated.An X-ray analysis offumagillin 261 has confirmed the constitution determined chemically, and' the structure of cephalosporin C has been deduced simultaneously from X-ray and chemical studies.262 Both in conformation and in molecular pack-ing, the sodium salt of the latter is markedly different from sodiumbenzylpenicillin. The molecule contains a fused /3-lactam-dihydrothiazine+Z Y*250M. Przybylska and L. Marion, Canad. J . Chem., 1961, 39, 2124.252 G. A. Sim, T. A. Hamor, I. C. Paul, and J. M. Robertson, Proc. Chem. SOC.,1961, 75.263 J. A. Hamilton, T. A. Hamoi, J. M. Robertson, and G. A. Sim, Proc. Chem. SOC.,1961, 63.254A. T. McPhail, J. M. Robertson, G. A. Sim, A.R. Battersby, H. F. Hodson,and D. A. Yeowell, Proc. Chem. SOC., 1961, 223.255 A. T. McPhail and G. A. Sim, Proc. Chem. SOC., 1961, 416; A. R. Battersby,D. A. Yeowell, L. M. Jackman, H.-D. Schroeder, M. Hesse, H. Hilterbrand, W. vonPhilipsborr, H. Schmid, and P. Karrer, ibid., p. 413.256 C. P. Saunderson and D. C. Hodgkin, Tetrahedron Letters, 1961, 16, 573; W. G.Dauben and P. Baumann, ibid., p. 565.257 J. S. Clunie and J. M. Robertson, J., 1961, 4382.258 M. Przybylska, Acta Cryst., 1961, 14, 424.259M. Przyb lska, Actu Cryst., 1961, 14, 429.260A. McL. &athieson and J. C. Taylor, Tetrahedron Letters, 1961, 17, 590.261N. J. McCorkindale and J. G. Sime, Proc. Chem. SOC., 1961, 331.26aD. C. Hodgkin and E. N. Maslen, Biochem. J., 1961, 79, 393; E.P. AbrahamJ. Fridrichsons and A. McL. Mathieson, Tetrahedron Letters, 1960, 26, 18.and G. G. F. Newton, ibid., p. 377SUTOR: ORGANIC STRUCTURES 479ring system (33) in place of the p-lactam-thiazolidine ring system of thepenicillins. In the crystal, nmide groups of successive molecules are hydro-gen-bonded in the direction of the b-axis (b = 4-99 A)7 an arrangement+ sH,N, 0 I \o=c,CH-CHz-CHl-CH,-C-NH-CH -CH CH,0-0 / I l lo*c - \ ,“CH,-O-C/:C MeI( 3 3)reminiscent of many peptide crystals where a short cell dimension (ca. 4.9 A)corresponds to the hydrogen-bonded distance between parallel peptidechains.There are two crystallographically independent but chemically similarmolecules in the crystal structure of ( +)-10-bromo-2-chloro-2-nitroso-camphane.263 The position of the buIky chlorine atoms, cis with respectto the CMe, bridge, causes some distortion of the amphane molecularframework and is the opposite configuration to that attributed to (-1-2-chloro-2-nitrosocamphane.In the latter connexion, it is perhaps significantthat the two compounds have Cotton effects of opposite sign. In (-)Abrorn0-2-nitrocamphane,~~* the halogen atom is also cis to the We, bridge.With the publication of a three-dimensional analysis of the y-form ofglycine, 265 the structures of all three polymorphs are known with consider-able accuracy. Corresponding bond lengths and angles are closely similar.The latest paper contains a discussion of the hydrogen-bond systems, andof the structural relation between the forms. The crystal structure ofasparagine monohydrate, NH2~CO*CH,*CH(NH,)*C0,H,H,0, has a t last beensolved.266 Although there is a short intramolecular distance (3.09 8)between the nitrogen atom of the amino-group and the oxygen of the amidegroup, the positions of the hydrogen atoms are consistent with this nitrogenatom forming three intermolecular hydrogen bonds with d(N-H-0) = 2-80,2.81, and 2.85 A. Hence, in the solid state, the molecule has an open-chainconfiguration, but the possibility of an intramolecular hydrogen bond insolution is not excluded. Direct evidence for the stability of the parallel-chain pleated sheet suggested by Pauling and Corey for a polypeptide chainhas been found in the crystal structure of the tripeptide glycylphenylalanyl-glycine. 267 Extended peptide chains are hydrogen-bonded together to forina parallel-chain pleated sheet of repeat distance 6.74 A which is a little longerthan the predicted value of 6.50 8. The benzene rings of the phenylalanineresidues protrude laterally and interlock with benzene rings of neighbouringsheets.@-Chitin268 is a monohydrate (in the dry state) of formula (C8H,,NO,,H,O),.263G. Ferguson, C. J. Fritchie, J. M. Robertson, and G. A. Sim, J . , 1961, 1976.zs4B. A. Brueckner, T. A. Hamor, J. M. Robertson, and G. A. Sim, Proc. Chem.266Y. Iitaka, Acta Cryst., 1961, 14, 1.sssG. Kartha and A. de Vries, Ndure, 1961, 192, 862.zs7R. E. Marsh and J. P. Glusker, Acta Cryst., 1961, 14, 1110.aaeN. E. Dweltz, Biochim. Biophys. Acta, 1961, 51, 283.SOC., 1961, 306480 CRYSTALLOGRAPHYThe N-acetylglucosamine rings are " chair " shaped and are linked throughthe l,.l;-positions forming a polysaccharide chain of repeat distance 10.3 A.The water molecules pack between the chains and more water can enterthere with increasing humidity. In connexion with the various models sug-gested for the different forms of cellulose, the structure of #l-cellobiose, adegradation product of cellulose I , is of some interest.21 Two " chair "-shaped B-glucose residues are linked in the 1,4-positions by an oxygen bridgewith L(C-O-C) = 117.5", and the length of the molecule 10.27 corre-sponds to the fibre axis of 10.3 A in all forms of cellulose. An intramolecularhydrogen bond stabilises the relative orientation of the two rings which aretwisted away from each other, and isolated molecules do not have a two-fold axis. The structure most closely resembles the bent and twisted con-formation suggested for cellulose I1 and later rejected.FIU. 2.coenzyme, as found in the wet crystals and viewed along one b axis and two a axes.The atomic position in one molecule cf the 5,6-diniethyEbenximidazolylcoba;ntirleI ) A(ii) the atoms of the nucleoside unit are marked by solid circles.(Reproduced, with permission, from P. G. Lenhert and D. C. Hodgkin, Nature, 1961,192, 938.)There is a preliminary report of the crystal structure of the 5,6-dimethyl-benzimidazolylcobamide coenzyme.269 The atoms have been located (seeFig. 2) and the formula of the molecule is given as C,,HlooCoN1801,P thoughthe exact number of hydrogen atoms is not yet certain. Apart from thecyanide group which has been replaced by an adenosyl residue, all the atomsof the vitamin B,, molecule appear to be present. This work representsanother great achievement in X-ray crystal structure analysis and furthersuccesses can be expected.D. J. S.W. COCHRAN. P. G. OWSTOW. D. J. SUTOR.zGaP. G. Lenhert and D. C. Hodgkin, Nature, 1961, 192, 937

ISSN:0365-6217    

DOI:10.1039/AR9615800453

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

INDEX O F AUTHORS’ NAMESAdbersberg, W. I. J., 443.Abe, H., 346.Abde Ali, 451.Abraham, E. P., 478.Abraham, R. J., 55, 57, 61,68, 71, 284, 288.Abraham, S., 365.Abrahams, S. C., 460.Abubakirov, N. K., 333.Aburto, S., 25.Acerbo, S. N., 237.Acharya, R. V., 180, 196.Acher, R., 314.Acheson, R. M., 264, 406.Achiwa, K., 302.Ackermann, D., 300.Aczel, T., 450.Adam, G., 297.Adams, D. M., 41, 106.Adams, G. A., 351, 352.Adams, R., 288.Adams, R. F., 210.Adams, R. M., 122.Adams, R. N., 441,-445.Adamson, A. W., 107.Addison, C. C., 80, 109,Ader, D., 407.Adley, T. J., 343.Adloff, J. P., 409.Adolph, H., 240.Adwani, S., 415.Affsprung, H. E., 405.Aftandilian, V. D., 82.Agaschkina, G. D., 130.Agata, I., 258.Ahearn, G. P., 202, 250.Ahmad, A., 206.Ahmad, M.S., 244.Aia, M. A., 81.Akagi, S., 324.Akahori, S., 74.Akhtar, M., 209, 329.Aksnis, G., 184.Albasiny, E. L., 27, 139.Albers, C. C., 252.Albert, A., 166.Alberti, G., 409.Alberts, A. W., 366.Alberts, G. S., 443.Album, H. E., 367.Alderweireldt, F., 252, 406.Aleksandrov, K. S., 453.Alexander, P., 300.Alexander, S., 58, 60, 150.Alfes, H., 347.Alfonsi, B., 440.Ali, M. A., 144, 156, 234.Ali, S. I., 426.131.QAlimarin, I. P., 401, 417,Alkema, H. J., 212.Allam, M. G., 425.Allan, E. A., 74.Allan, J. E., 438.Allavena, M., 27.Allegra, G., 464.Allen, A. D., 184.Allen, B., 440.Allen, C. R., 165.Allen, D. S., 299.Allen, G., 36.Allen, J. C., 208, 216.Allen, L. C., 22, 25, 41, 139.Allen, M.J., 180.Allen, R. G., 191.Allerhand, A., 62.Alleston, D. L., 93.Allinger, J., 41, 196.Allinger, N. L., 41, 180, 193,195, 196, 230, 248, 323.Allphin, N. L., 430.Allport, D. C., 214.Allport, J. J., 30, 46.Almenningen, A., 196, 247.Alon, A., 407.Alperin, H. A., 456, 457.Althouse, V. A., 208.Altman, K. I., 378.Alvarez, R., 435.Amberg, C. H., 45.Amberger, E., 99.Ambrose, J. R., 101.Ames, D. E., 213, 219.Amiya, T., 298.Amma, E. L., 462.Amme, R. C., 31, 33.Amoros, J. L., 459.Amos, A. T., 22, 145, 152.Amundsen, L. H., 264.Ananchenko, S. N., 332.Anand, N., 287, 352.Anand, V. D., 402.Anbar, M., 99.Anderer, F. A., 319.Anders, 0. U., 448.Andersen, A. F., 457.-4ndersen, C. C., 345.Andersen, E., 158.Anderson, D.H., 150, 152.Anderson, D. M. W., 266,Anderson, G., 400.Anderson, G. R., 102.Anderson, G. W., 306, 307.Anderson, J. L., 216.Anderson, N. G., 406.Anderson, 0. L., 46.421.350, 439.48 1Anderson, R. A., 304.Anderson, R. S., 210.Andersson, S., 123.Andreeva, N. S., 375.Andrews, L. J., 101, 163.Androes, G., 67.Anduze, R. A., 425.Anesey, J., 369.Anet, E. F. L. J., 336.Anet, F. A. L.,. 57, 58, 61,Anfinsen, C. B., 320.Angell, C. L., 42.Anger, V., 403.Angoletta, M., 120.Angus, H. J. F., 223.Angyal, S. J., 341.Anh-Hoa, H., 197.Anisimov, K. N., 108.Ankel, T., 56.Annaka, S., 459.Anner, G., 330, 331.Anneser, E., 270.Annino, R., 442.h i s , J. L., 450.Anno, T., 144, 145.Ansell, M. F., 203, 242.Anselment, W., 85.Anson, F.C., 412, 424.Anthony, W. C., 277.Antia, M. B., 401.Antia, N. J., 339.Antipova, T. A., 429.Anton, A., 425.Aoki, T., 289.Appel, K., 21.Appel, R., 100.Appelman, E. H., 103.Applegarth, F., 207.Applequist, D. E., 238.Applewhite, T. H., 322.Arai, T., 140, 142.Arakawa, H., 283.Arakawa, K., 314.Araki, C., 350, 351, 448.ArAneo, A., 120.Arata, Y., 59, 74.Aravindakshan, C., 455.Arbuzov, B. A., 68.Archer, G., 154.Archer, S., 287.Archibald, A. R., 349.Archibald, L. B., 36.Arcus, A. C., 406.Arens, J. F., 212.Arigoni, D., 217, 330.Arison, B. H., 68, 322.Ariyoshi, U., 346.Arlt, H. G., jun., 199.119482 INDEX OF AUTHORS’ NAMESh a r e g o , W. L. F., 166.Armour, A. G., 92.Armour, C., 176, 337.Amdt, C., 214.Amdt, U.W., 453.Arnet, J. E., 114.Arnett, E. M., 155,181,223.Arnold, W., 293, 294.Aronsson, B., 103, 461.Arora, R. C., 401.Arotsky, J., 102.Arthur, H. R., 258.Arthur, P., 441.Arya, L. V. P., 256.Asai, S., 45,Asano, T., 235.Aselius, J., 461.Ashida, T., 472, 476.Ashworth, M. R. F., 437.Asinger, F., 267, 270.Asker, W., 267.Aso, K., 345.Aspinall, G. O., 352.Asprey, L. B., 79, 122, 460.Asscher, M., 220.Asselineau, C., 218, 255,Asselineau, J., 218, 219,Astakhova, L. I., 472.Astbury, W. T., 375, 377.Aten, A. H. W., 446.Aten, C. F., 49.Athevale, V. T., 420, 442.Atkinson, V. A., 196, 246.Attenburrow, J., 326.Audrieth, L. F., 97.Augustine, R. L., 297.Aurivillius, K., 470.Austrup, R., 267.Autrey, R.L., 258.Averill, W., 410.Avram, M., 233.Awe, W., 289.Axelrod, L. R., 406.Axtermann, R. T., 76.Ayers, B. O., 410.Aylward, F., 201.Ayphassorho, C., 323.Ayres, W. M., 443.AzSroff, L. V., 134.Azumi, M., 130.Amott, s., 477.257.301.Baaz, M., 96.Babe, H., 146, 147, 448.Babb, R. M., 221.Babin, E. P., 159.Babko, A. K., 434.Bach, B., 248.Bach, H., 206.Bachawat, B. K., 360.Bachmann, G., 237.Bachra, B. N., 378.Backsai, R., 157.Bacon, R. G. R., 230.Baddeley, G., 244.Baddeley, G. V., 259.Bader, A. R., 277.Bader, R. F. W., 155.Bader, R. W., 186.Badger, G. M., 260.Bilckman, M., 461.Baehler, B., 302.Baenziger, N. C., 113, 119,Biirnighausen, H., 269,466,Bafus, D., 75.Bafus, D.A., 80.Bagby, M. O., 218.Baggett, N., 67, 273.Bagley, F. D., 186.Bagli, J. F., 202,Bagnall, K. W., 122.Bagnell, J. J., 221.Bailar, J. C., jun., 106, 107.Bailey, P. H., 401.Baiocchi, F., 207.Baiulescu, G., 421.Bak, B., 144, 166.Bak, T. A., 158.Baker, E. D., 84.Baker, 5. A., 219.Baker, P. R. W., 430.Baker, R., 160.Baker, R. W. R., 219.Baker, W., 227, 228, 233.Bakker, G. H., 229.Balaban, A. T., 274.BSlan, Gh., 407.Balashova, L. D., 98.Balazs, E. A., 68.Balazs, L., 428.Balchin, L. A., 442.Baldeschwieler, J. D., 43,Baldwin, M. E., 105.Balenovid, K., 190, 192,Baliah, V., 165, 229.Ball, W. E., 49.Ball, W. J., 214, 244.Ballreich, K., 131.Balls, W. J., 178.Balo, J., 372.Ban, Y., 291.Banerjee, B., 127.Banerjee, N.G., 416.Baney, R. H., 89.Banga, I., 372.Bank, S., 174, 245.Banks, B. E. C., 176, 337.Banks, R. E., 101.Banks, W., 349.Banwell, C. N., 56, 59, 61.Banyard, K. E., 456.Ban-yuan, U., 97.Barash, L., 193.Barber, G. A., 365.Barber, M., 103.464.476.63, 70.221.Barber, M. S., 68, 216, 217.Bmbier, M., 218.Barbiroli, G., 403.Barbour, A. K., 224.Barbulescu, N., 268.Barclay, G. A., 104, 128,132, 133, 134, 468, 471.Barclay, L. R. C., 181, 223.Bard, A. J., 423, 424.Barendrecht, E., 400, 419,Bafield, P. A., 83.Barker, G. C., 446.Barker, I. R. L., 337.Barker, S. A., 342,343,345,BBrlSdeanu, L., 175.Barltrop, J. A., 206, 254.Barnard, A. K., 128.Barnard, P. W. C., 183,184.Barnes, R. A., 282.Barnett, G.A., 445, 449.Barnun, L. H., 429.Barb, M., 276.Barraclough, C. G., 41, 105.Barreto, H. 8. R., 407.Barreto, R. C. R., 407.Barron, E. J., 365.Barry, D. L., 429.Barry, J. C., 407.Barry, J. E., 164, 173.Barry, V. C., 346.Bartell, L. S., 155.Bartkus, 33. A., 167.Bartlett, N., 91, 100, 132.Bartlett, P. D., 116, 166,Bartlett, P. O., 174.Rartley, W., 395.Bartley, W. J., 239.Bartocha, B., 86.Barton, C. J., 122.Barton, D. H. R., 179, 209,253, 258, 259, 260, 285,296, 323, 325, 326, 327,329, 330.422.347.245.Barton, G. W., 450.Bartz, Q. R., 339.Basargin, N. N., 432.Baach, A., 328, 335.Baschang-Bister, W., 343.Basco, N., 29, 51.Basiriski, A., 437.Basolo, F., 104, 106, 107,Bass, C. D., 43.Bastiansen, O., 196, 247.Basu, S., 145, 278.Bates, D.R., 22.Bates, R. G., 400.Bator, B., 306.Battersby, A. R., 285, 286,Battiste, M., 239.Battiste, M. A., 232, 239.Bauer, E., 35, 51.108.289, 292, 293, 478INDEX OF AUTHORS’ NAMES 483Bauer, H., 267.Bauer, H. H., 444.Bauer, H. J., 30.Bauer, I., 111Bauer, M., 242.Bauer, R., 80.Bauer, S., 332.Bauer, S: H., 46.Bauer, V. J., 194, 247, 296,BauerovB, O., 332.Baughman, G. A., 91, 175.Baum, M. E., 174.Baumann, P., 478.Baumann, U., 380.Baumgartner, F., 118.Baumgmte, G., 267.Baunok, I., 125.Baxter, R. M., 285.Bayer, I., 418.Bayliss, N. S., 36, 38.Beach, W. F., 60, 276.Beachell, H. C., 82.Beadle, G. W., 383.Beak, P., 254, 255, 256.Beamish, F. E., 411, 433.Beard, H.C., 404.Beaton, J. H., 329, 330.Beaton, J. M., 209.Beattie, A., 350.Beattie, I. R., 90.Beattie, W. H., 437.Beaucamp, K., 396.Beauxis, J. O., 450.Beaven, G. H., 163.Becher, H. J., 461.Beck, F., 181.Beck, M. T., 417.Beck, P., 204.Beck, W., 109, 119.Becka, L. N., 455.Becke-Goehring, M., 90, 98,99, 101, 261.Becker, E., 378.Becker, E. D., 43, 68, 284.Becker, R., 30.Becker, R. S., 40.Becker, W. E., 93.Beckman, O., 468.Beckmann, R., 381.Beckmann, S., 245.Beckwith, A. L. J., 231.Begemann, P. H., 219, 402.Beglinger, U., 297.Behrens, H., 98, 109, 110.Beiler, T., 301.Beinert, H., 353, 358.Belardini, M., 256.Belcher, R., 481, 436.Belen’kii, L. I., 186.Beletskaya, I. P., 168.Bell, A., 239.Bell, M. R., 287.Bell, R.P., 154, 163, 179,Bell, T. T., 389.325.183.Bellamy, L. J., 37, 38, 41.Belleau, B., 286.Belles, F. E., 47.Bender, M., 312.Bender, M. L., 180, 181.B6n6, G., 73.Ben-Efrain, D. A., 204,205,215, 234.BenegovB, V., 252.Benington, F., 289.Benigek, L., 444.Benjamin, B. M., 192.Benkeser, R. A., 284.Bennett, M. A,, 69.Bennett, R. P., 230.Bens, E. M., 409.Bensiton, L., 321.Benson, A., 38.Benson, R. E., 69, 215.Bensusan, H. B., 377.Bent, H. A., 43, 79.Bentley, J. P., 378.Bentley, K. W., 290.Bentley, R., 265.Ben-Yair, M. P., 452.Benyon, J. H., 450.Benz, R., 122.Benzing, E., 283.BerAk, L., 413.Bertinkovb, Z., 315.Berchtold, G. A., 243.Berbik, J., 425.Berdahl, J. M., 189, 247.Berde, B., 314.Berger, A., 236.Berger, H.G., 213.Berger, J. G., 179, 238.Berger, R., 221.Berglund, C., 202, 266.Bergmann, E., 170.Bergmann, E. D., 222.Bergmann, F., 279.Bergmann, W., 219.Bergsma, J., 460.Bergstrom, G., 64.Berhenke, L. F., 400.Berka, A., 422, 445.Berkoff, C. E., 233.Berkowitz, J., 80.Berlin, A., 452.Berlin, A. A.; 103.Berlin, A. J., 66, 194, 196.Berlin, A. M., 117.Berlin, A. S., 351.Berliner, E., 163.Bernal, M. J. M., 22.Bernas, B., 414.Berndt, W., 415.Bernheim, R. A., 78.Bernsee, G., 338.Bernstein, H. J., 55, 57,61, 149, 288.Berry, D. S., 64.Berry, J. W., 429.Berry, R. S., 157.Bersohn, M., 207.Bersohn, R., 149, 151.Berson, J. A,, 192, 193,245.Bertelli, D. J., 113,156,236.Berthelot, M., 222.Berthier, G., 25.Bertho, A., 292.Berti, G., 277.Bertin, D., 333.Bertsch, H., 341.Bessis, G., 27.Bestmann, H.J., 203.Betheil, J. J., 373.Bevan, C. W. L., 220.Beyerman, H. C., 306, 314.Bezas, B., 306.Bezman, I. I. 97.Bhaduri, B. P., 416.Bhakuni, D. S., 287.Bharucha, M., 333.Bhat, A. N., 411.Bhatnagar, M. L., 425.Bhatnagar, R. P., 401.Bhattacharya, R., 147.Bhattacharyya, A., 346.Bhattacharyya, A. C., 416.Bhattacharyya, S. C., 251.Bheemasankara Rao, Ch.,Bick, I. R. C., 68, 290.Bicking, J. B., 395.Bicknell, R. C., 185.Biekert, E., 378, 379, 380,Bielski, B. H. J., 99.Biemann, K., 301, 304.Bier, H., 111.Biernat, J. F., 306.Bierwirth, E., 305.Bigler, F., 321.Bigley, B., 327.Bigley, D. B., 199, 206.Bigot, J.A., 206.Bilbo, A. J., 86.Bilefield, L. I., 447.Billing, C. J., 162.Billingham, E. J., jun., 452.Billman, J. H., 200.Billy, M., 90.Binaghi, M., 221.Binder, I., 462.Bingel, W. A., 26.Binger, P., 82, 237.Binkert, J., 339.Binks, R., 285.Binns, S. D., 288.Birch, A. J., 220, 281, 292.Birch, T. W., 355.Birchall, J. M., 82, 224.Bird, C. W., 195, 246.Bird, T. P., 343.Birkhimer, E. A., 158.Birkofer, L., 200, 305.Birnbaum, G., 207.Birss, F. W., 27, 139.Biserte, G., 311.Bishara, S. W., 436.411.381, 382484 INDEX OF AUTHORS’ NAMESBishop, C. A., 185.Bishop, C. T., 351.Bishop, E., 414, 419, 427.Bishop, E. O., 55, 59, 68,Bishop, E. T., 438.Biswas, A. B., 471.Bither, T. A,, 96.Bitovt, Z. A., 401.Bitter, B., 165.Bittler, K., 117.Bitton, D., 51.Bjerrum, J., 126.Black, W.A. P., 343.Blackman, N., 50.Blackman, V., 29.Blackwell, I. G., 425.Blackwell, R. Q., 304.Blades, J., 219.Blaedel, W. J., 441, 443,446, 448.Blake, D., 92.Blake, G. G., 428.Blakely, C. F., 240.Blalock, T. J., 415.Bland, J. A., 123, 469.Blatter, H. M., 195, 206,Blay, N. J., 82.Blecha, J., 416.Bledsoe, J. O., 221.Blinc, R., 76.Bliss, A., 81.Bloch, K., 218.Block, R. J., 300.Blomquist, A. T., 190, 238,Bloom, S. M., 282.Bloodeld, J. J., 207.Blow, D. M., 454.Blues, E. T., 230.Blum, R., 347.Bly, R. S., 171.Blythe, A. R., 33.Blythe, P. A., 48.Boase, D. G., 435.Bobbitt, J. M., 264.Bock, H., 95.Bock, M., 341.Bock, R. M., 358. -Bodanszky, M., 307, 314.Bode, H., 79.Bode, J.D., 404.Boden, H., 206.Bodesheim, F., 201.Bockmann, A., 347.Boedtker, H., 367.Bohni, E., 311.Boekelheide, V., 272, 282,Boettcher, F.-P., 279.Bogdan, E., 134.Bognhr, J., 402.Bognhr, R., 341.Bogomolny, A. M., 46.Bogue, D. C., 304.322.323.240.293.Bohlen, D. H., 201.Bohlmann, F., 214, 286.Boikess, R., 239.Boisselle, A. P., 212.Boissonnas, R. A., 313, 314,Boit, H. G., 294.Bokadia, M. M., 68.Bokii, G. B., 111, 468.Boldin, A. A., 438.Bolschakov, K. A., 130.Bolze, C., 207.Bonamico, M., 476.Bond, W. L., 460.Bonera, G., 78.Bonitz, E., 87.Bonnema, J., 212.Bonner, D. M., 383, 385,Bonner, H., 392.Bonner, J., 392.Bonner, W. A., 177, 192,Bonnett, M., 145.Bonnett, R., 278.Bonsels, W., 445.Bontekoe, J.S., 306, 314.Booman, G. L., 404, 405,Boone, J. L., 83, 85.Boonstra, E. G., 473.Booth, G., 119.Booth, V. H., 407.Bor, G., 109.BorEi6, S., 238.Borden, G. W., 243.Boreckf, J., 407.Bornmann, P., 91.Boronowski, H., 214.Borowitz, S., 19.Bory, S., 255.Boryta, D. A., 452.Bose, A. K., 323.Bose, S. K., 312.Bose, S. M., 374.Bosshard, H. H.,Boswijk, K. H., 101.Bothner-By, A. A., 60, 68,71, 155, 181.Bouchauden, J., 217.Boudart, M., 46.Boiidakian, M. M., 198,231.Bouissi&res, G., 121.Boulton, A. J., 268.Bourne, E. J., 336,337,345,Bourns, A. N., 171, 186.Bouten, P., 447.Bouveng, H. O., 351.Bovey, F. A., 68, 78, 305.Bowen, D. M., 282.Bowen, E. J., 434.Bowen, H. J.M., 447.Bower, V. E., 400.Boweran, M. G., 460.Bowers, A., 326.315, 316.386.282, 340, 343, 344.448, 449.378.Bowes, J. H., 368, 372, 373.Boyce, C. B., 195, 248.Boyd, C. M., 423.Boyd, R. H., 153, 171.Boyden, F. M., 132.Boyer, J. H., 272.Boyer, P. D., 302.Boys, S. F., 15, 22, 28, 139,Brabbs, T. A., 47.Brackel, H., 286.Bradley, D. C., 126.Bradley, J. N., 47, 49, 178,Bradley, R. B., 68, 284.Bradley, R. M., 362.Bradsher, C. K., 289.Brady, R. O., 353,359,360,BrBndle, K., 101.Brandle, K. A., 93.Bragg, P., 337.Braibanti, A., 470.Braillon, B., 56, 60.Braman, R. S., 432.Brand, J. C. D., 41.Brandenberger, S. G., 203.Brandon, D. D., jun., 216.Brandon, R. L., 228.Brandsma, L., 212.Brandts, J., 305.Brannock, K.C., 239.Bratek, M. D., 286.Bratoi, S., 27.Brauer, G., 460.Brauner, P. A., 413.Braunitzer, G., 317.Braunschweiger, H., 283.Bray, P. J., 77, 151.Braye, E. H., 284.Bready, J. C., 433.Rreazeale, J. D., 132.Breazeale, M. A., 30.Bredehorst, H., 434.Bredenberg, J. B.-S., 253.Bredereck, H., 172, 219,Breene, R. G., 11.Bregovec, T., 192.Brehler, B., 470.Brendel, K., 190, 212.Brennan, G. L., 84.Brenner, M., 309.Brenner, N., 304.Brenner-Holzach, O., 280.Breslow, D. S., 114, 119,Breslow, R., 170, 231, 239,Bresnick, E., 394.Bressler, R., 361.Breuer, S. W., 285.Brewer, L., 103.Brewer, P. I., 406.Brewis, S., 258.Brewster, J. A., 132.140.221.362.279.236.395INDEX OF AUTHORS’ NAMES 485Brewster, J.H., 190.Brey, W. S., 83.Brgovec, I., 221.Briant, J., 420.Bridgwater, R. J., 277.Brient, S. J., 26.Briggs, C. K., 299.Briggs, L. H., 257, 297.Briggs, R., 441.Brigman, G. H., 26.Brimacombe, D. A., 158.Brimacombe, E., 338.Brimacombe, J. P., 338,Brindley, D. J., 442.Brinen, J. S., 146.Brion, H., 26, 139, 142.Brion, H. L., 151.Britton, D., 49.Broadbank, R. W. C., 401.Brocklehurst, P., 145.Brockmann, H., 310.Brogin, 0. V., 263.Brois, S. J., 261.Brook, A. J., 165.Brooke, G. M., 224, 225.Brooks, C. J. W., 41.Brooks, R. R., 404.Brooks, S., 341.Broomhead, J. A., 428.Brosset, C., 129, 466.Brotherton, B. J., 83.Brotherton, R. J., 85.Brower, K. R., 179.Brown, B. R., 68, 260.Brown, B. T., 333.Brown, D. J., 166, 275.Brown, F.C., 266.Brown, G. M., 390, 395.Brown, H. C., 81, 198, 199,200, 203, 213, 216, 242,261.342.Brown, H. W., 43.Brown, I. D., 133, 465.Brown, J. C., 155.Brown, J. H., jun., 197.Brown, M. P., 69.Brown, R. A., 410.Brown, R. D., 144,147,158.Brown, R. J. S., 57.Brown, R. K., 320, 344.Brown, R. N., 476.Brown, R. R., 381.Brown, T. H., 152.Brown, T. L., 41, 80.Brown, W. D., 304.Brown, W. H., 217.Brown, W. L., 453.Browning, M. C., 131.Brownlee, M. J., 183.Brownstein, S., 58, 149, 159.Bruckenstein, S., 446.Brueckner, B. A., 479.Brueckner, D. A., 249.Bruckner, K., 324.Briigel, W., 56.Brugmann, G., 334.Brufani, M., 476.Bruice, T. C., 180, 181.Brucker, A. B., 98.Bruckl, A., 121.Brunner, H., 118, 157.Bruno, G., 82.Bruno, J.J., 181.Bryan, C. E., 264.Bryan, R. F., 467, 477.Bryant, D. R., 207, 264.Bryce, W. A., 410.Bryce-Smith, D., 81, 208,211, 223, 224, 230.Bryden, J. H., 473.Brzobohat4, J., 414.Bublitz, D. E., 86, 117.Buchanan, M. A., 289.Buchanan, R. F., 448.Buchi, G., 253.Buchman, E. R., 392.Buck, K. W., 340.Buckingham, A. D., 8, 35,Buckler, S. A., 222.Buckles, R. E., 39.Bucourt, R., 332.Buddecke, E., 373.Budevski, O., 416.Budnowski, M., 270.Budzikiewica, H., 277.Budzko, D. B., 403.Buchi, G., 283.Buchler, W., 440.Biirger, G., 114.Buettner-Janusch, V., 315,Buijs, K., 44.Bulanin, M. O., 42.Bulewicz, E. M., 50.Bullen, G. J., 98, 132, 462,Bu’Lock, J. D., 214.Bumgardner, C. L., 237.Bumpus, F.M., 314.Buncel, E., 164, 171.Bunker, D. L., 51, 53.Bunnenberg, E., 302.Bunnett, J. F., 154, 164,285.Bunton, C. A., 156, 159,176, 181, 182, 183, 185,337.71, 72, 149.316.466.Buraway, A., 145.Burdon, J., 224, 225.Burg, A. B., 84, 91, 96, 97.Burgstahler, A. W., 208,Burke, H. J., 196.Burke, J. J., 62, 93.Burkhard, W. J., 135.Burnell, R. H., 298.Burnelle, L., 27, 139.Burns, G., 48.Burns, R. G., 173.Burpitt, R. D., 239.255.Burr, G. O., 355.Burr, M. M., 355.Burriel-Marti, F., 433.Burroughs, L. F., 301.Burstall, M. L., 179.Burtner, R. R., 201.Burton, J. S., 338.Burton, R., 69, 113.Burwell, R. L., 154.Busch, D. H., 107, 129, 131.Busev, A. I., 416, 425.Bush, I. E., 321.Bush, M. T., 405.Bushick, R. D., 155, 181.Butenandt, A., 220, 378,Butler, A.R., 182.Butler, F. E., 449.Butsugan, Y., 287.Butt, A., 266.Butterworth, D. E., 429.Buxton, M. W., 224.Buyske, D. A., 430.Byrne, J. T., 446.Byron, S., 50.Bystrov, V. E., 66.379, 380, 381, 382.Cable, J. W., 456.Cabrera, G., 373.Cadist, P., 221.Cadogan, J. I. G., 208, 216.Cady, G. H., 100.Cahill, D., 448.Caine, D., 251.Cainelli, G., 330.Cairns, T. L., 213, 223.Cairns-Smith, A. G., 281.Cais, M., 118, 237.Caldin, E. F., 165.Caldini, O., 411.Caldow, G. L., 20, 40, 42.Cales, H. M., 285.Callahan, F. M., 306, 307.Callear, A. B., 29, 51.Calvert, J. G., 209.Calvert, L. D., 128.Calvin, M., 67.Camac, M., 29, 46, 47.Cambie, R. C., 256, 257,Camerino, B., 324.Camiener, G.W., 390.Camp, A. V., 335.Campbell, H. J., 154.Campbell, I. G. M., 190.Campbell, N., 281.Campbell, R. B., 475.Campbell, R. D., 279.Canceill, J., 328.Cannon, C. G., 36, 42.Cannon, P., 420.Canonica, L., 240.Cantacuzene, J., 75.Canterino, P. J., 223.Canut, M. L., 459.297486 INDEX OF AUTHORS’ NAMESCanziani, F., 110, 120.Caplier, I., 284.Capomaggi, A. S., 209, 330.Capuano, I. A., 420.Cargill, R. L., 242.Carlson, G. L., 395.Carlton, T. S., 121.Carrnan, R. M., 255.Carnegie, P. R., 304.Carotti, A. A., 87.Carpenter, C., 113, 464.Carpenter, F. H., 306.Carpenter, G. B., 456.Carpino, B. A., 305.Carpino, L. A., 305.Carr, A. D., 405.Carra, S., 145.Carrick, N. L., 112.Carrington, A., 103, 149.Carrington, T., 34.Carrington, T.R., 324.Carrion, J. P. 310.Carriuolo, J., 181.Carroll, F. I., 221.Carroll, R. J., 368.Carter, H. E., 300.Carter, P., 174.Carter, R. E., 65, 151.Cartmell, A,, 79.Cartwright, P. F. S., 412.Casanova, J., jun., 249.Casapieri, A., 173.Case, C. T., 47.Case, J. R., 100, 221.Caserio, F. F., jun., 216Caserio, BI. C., 238.Cash, A. H., 460.Casinovi, G. C., 287.Cason, A., 460.Cason, D. L., 102.Cason, J., 205.Castellano, S., 56, 60.Castle, J. E., 216.Caswell, H., 220.Caswell, L. R., 279.Catalano, E., 43.Catherino, H. A., 441.Catlette, W. H., 262.Caumartin, J., 322.Crtva, M. P., 227, 228.Cavanagh, L. A., 423.Cavanaugh, J. R., 56, 64.Cavell, E. A. S., 172, 179.Cavell, R. G., 124.Cavill, G.W. K., 248.Cawse, P. A., 447.Ceciarelli, L., 111.Ceder, O., 293.Cekan, Z., 321, 332.Celikovskh, G., 407.Cella, J. A., 201.Cerecedo, L. R., 394.Cereghetti, M., 331.Cerfontsin, H., 158, 169.b r n i k , V., 305.cern3, M., 339.Gem?, V., 321.Cervinka, O., 265, 271.Cesca, S., 86.Chabudzinski, Z., 249.ChaikoR, I. L., 365.Chakravarti, S. K., 422.Chalaya, Z. I., 434.Chamberland, B. L., 99.Chamberlin, J. W., 325.Chambers, D. W. S., 90.Chambers, R. D., 93, 102,Chambers, R. W., 275.Champion, N. G. S., 84.Chan, F. L., 413.Chandra, A. K., 145.Chaney, A., 341.Chang, H. W., 231.Chang, S. S., 410.Chang, T. L., 441.Chapman, A. C., 97, 98.Chapman, D., 101.Chapman, J. A., 371.Chapman, J. H., 322.Chapman, N.B., 179, 196.Chapman, 0. L., 64, 235,Channan, H. B., 75, 167,Charney, E., 188.Charney, W., 335.Charnov, R. V., 123.Chatt, J., 104, 118, 119,120, 124, 127.Chatten, L. G., 417.Chaudet, J. H., 435.Chaudhry, G. R., 323.Chauvet, J., 314.Chekula, I. A., 36.Chen, C., 322.Chen, K. K., 333.Chen, T. C., 22.Cheng, F. W., 429.Cheng, K. L., 415.Cherbuliez, E., 302.Cherdron, H., 410.Cherkesov, A. I., 434.Chernik, C. L., 127, 128,Chernobai, V. T., 332.Chernyaev, I. I., 107, 130.Chesters, G., 451.Chestnut, D. B., 152.Cheswick, J. P., 62.Cheung, T. H., 260.Chevalier, E. C., 444.Chiang, Y., 153, 154.Chiaramonti, D., 326.Chibnall, A. C., 220.Chidambaran, R., 457.Chien, J. C. W., 69, 114.Child, H. R., 456.Childers, E.E., 400.Chilwell, E. D., 399.Chimiak, A., 306.Chinn, L. J., 332.432.242, 243.168.130.Chiodi, L., 78.Chirgadze, Y. N., 375.Chirkov, N. M., 153.Chirnside, R. C., 398.Chisholm, M. J., 218.Chissick, S. S., 167.Chistyakov, J. G., 453.Chiurdoghu, G., 41, 247,Choguill, H. S., 154.Cholnoky, L., 217.Chopard-dit-Jean, L. H.,Chopoorian, J. A,, 120.Chovin, P., 409.Chow, W. Z., 253.Chow, Y., 256.CMtien, A., 126.Christ, H. A., 66.Christensen, D., 166.Christensen, J. E., 344.Christie, T. I., 104.Christman, D. R., 378.Christmann, O., 272.Christy, M. E., 263.Chromf, V., 415.Chubb, F. L., 270.Chubukova, T. M., 452.Chung, D., 316.Church, R. F., 254, 255.Chvapil, M., 371.Cipera, J. D., 315.Citron, I., 438.Ciiek, J., 158.Claassen, H.H., 128, 130.Claeson, G., 67.Clancy, M. J., 341, 342.Clar, C. T., 144.Clark, B. F. C., 403.Clark, H. C., 93, 94, 124,Clark, R. J. H., 123, 466.Clark, R. O., 435.Clark, R. T., 445.Clark, V. M., 237.Clarke, F. H., jun., 251.Clarke, H. T., 373.Clarke, J. K. A., 45.Clarke, R. L., 323.Clark-Lewis, J. W., 68,Clasen, H., 85.Claunch, R. T., 104.Clayton, R. B., 322.Clementi, E., 26, 27, 139.Clementi, F., 101.Clerc, R. J., 451.Clezy, P. S., 290.Clinkscales, J. K., 428.Clinton, R. O., 323.Closs, G. L., 221, 239,Closs, L. E., 221, 239.Closson, R. D., 118.Closson, W. D., 175.Clough, F. B., 189.252, 253.311.132.283.261INClouston, J. G., 28.Clunie, J. S., 253, 478.Coates, G.E., 80, 83, 92.Cobble, J. W., 129.Coblentz, F. L., 200.Cochran, J. C., 164.Cochran, W., 457.Coda, A., 476.Coe, J. S., 176.Coe, P. L., 224.Cormos, D., 424.Coffield, T. H., 118.Coffman, D. D., 96, 208.Cohan, N. V., 25.Cohen, A., 47, 144.Cohen, A. I., 412.Cohen, J., 289, 369.Cohen, J. A., 321.Cohen, L. A., 302, 303.Cohen, M., 19, 22.Cohen, T., 155, 181, 209,Cohen-Bazire, G., 385.Cohn, H., 162.Cokal, E. J., 423.Coke, J. L., 248.Colburn, C. B., 94.Colby, T. H., 245.Cole, A. R. H., 36, 38.Cole, R. M., 49.Coleman, J. S., 122.Coleman, R. F., 446.Coleman, W. E., 227, 228.Colinese, D. L., 246.Collier, H. 0. J., 313.Collins, C. J., 192, 279.Collins, R., 93.Collman, J. P., 105.Colowick, S.P., 385.Colton, R., 128.Colvin, D. W., 419.Combe, M. G., 241.Companion, A. L., 25.Compling, L. M., 355.Condal-Bosch, L., 438.Condo, F. E., 348.Conduit, C. P., 37.Conger, R. P., 264.Connally, R. E., 423, 424.Conner, W. S., 399.Connett, J. E., 326.Connick, R. E., 129.Connolly, D. J., 238.Connolly, J. D., 250.Connolly, J. W., 221.Connor, T. M., 74.Connors, K. A., 181.Conrow, K., 231.Consden, R., 372.Conte, A., 409.Coogan, C. K., 77.Cook, D. C., 39.Cook, G. B., 15.Cook, S. E., 93.Cook, W. A., 431.Cooke, G. H., 181.285.EX OF AUTHORS’ NAMES 487Cooke, W. D.; 441.Cookson, R. C:, 188, 195,223, 231, 233, 237, 240,246.Coolidge, A. S., 24, 26.Coon, M. J., 360.Coon, R. I., 71.Cooper, A. S., 460.Cooper, J.R. A., 27, 139.Cope, A. C., 177, 193, 215,Coppola, F., 476.Corbett, G. E., 165, 231.Corbett, J. D., 121, 135.Corbett, W. M., 337, 348.Corbridge, D. E. C., 134.Corey, E. J., 68, 95, 170,Corey, E. R., 109.Corio, P. L., 55, 149.Corliss, L., 456.Cornille, M,, 27.Corradini, P., 464.Corral, R. A., 299.Corwin, A. H., 284.Coscarelli, W., 335.Cosmatos, A., 306.Costopanagio tis, A., 3 14.Cotlove, E., 421.Cotton, F. A., 67, 105, 130,Cottrell, T. L., 28, 31, 33.Coulson, C. A., 7, 9, 11, 20,22, 24, 38, 79, 139, 141,143,144, 148, 156, 234.243.196, 201, 249, 251, 283.132, 133.Coulson, D. M., 423.Courtney, J. L., 259.Courtois, J. E., 336, 346.Courtot, P., 242.Courts, A., 369, 372.Coussmaker, C. R. C., 131Cowan, P.M., 375.Cowie, G. R., 177.Cox, D. A., 237.Cox, E. G., 134.Cox, G. F., 81.Cox, J. S. G., 68, 322.Cox, S. J., 413.Coxon, B., 340, 342, 343,Coyle, T. D., 60, 62, 66, 67,Crabb, T., 293.Crabtree, A., 271.Crabtree, J. M., 104.Craig, D. P., 139, 146, 156.Craig, J. C., 203.Craig, L. C., 312.Cram, D. J., 169, 170, 186,Cramer, F., 267, 307.Cramer, R., 268.Crane, F. L., 358.Crapo, L. M., 68.Craven, B. M., 132, 468.Crawford, A,, 43 1.345.119.225.Crawford, B. L., 43.Crawford, I. P., 386, 387,Crepy, D., 314.Crespi, H. L., 177, 284.Cresswell, R. M., 281.Crick, F. H. C., 375, 377,Criddle, W. J., 336.Criegee, R., 115, 233.Cripps, H. N., 114, 236.Cristiani, G. F., 206, 262.Cristd, S. J., 171, 206.Critchfield, F.E., 438.Crittenden, A. L., 441.Cromartie, R. I. T., 241.Cromartie, R. J. T., 379.Crombie, L., 68, 248, 283.Crompton, B. A., 408.Cropp, D. T., 323.Cross, A. D., 260, 334.Cross, B., 202, 241.Cross, B. E., 257.Cross, G. L., 264.Crowell, T. I., 171.Cruickshank, D. W. J., 144,Crunden, E. W., 181.Crundwell, E., 246.Csavinszky, P., 25.Cuisa, W., 403.Culbertson, T. P., 342.Cullen, E., 230.Cullis, C. F., 410.Culvenor, C. C. J., 288.Cundiff, R. H., 418, 426.Cunliffe-Jones, D., 42.Cunningham, B. B., 460.Cunningham, L. D., 321.Cunningham, W. L., 351.Curby, R. J., 180.Curl, R. F., 43.Curte, R., 476.Curtin, D. Y., 197, 209.Curtis, N. F., 131.Curtis, R. F., 234.Custard, H. C., 284.Cutler, D., 78.Czack, A., 307.Czarecki, K., 422.388.388.455.Dabkowska, M., 444.Dacons, J.C., 277.Daecke, H., 403.D&hne, W., 127.Dafeldecker, W., 343.Dahl, G. H., 83, 84.Dahl, L. F., 109, 110, 115,Dahms, G., 280.Dahn, H., 66, 153.Daiber, J. W., 48.Dailey, B. P., 56, 64, 72,Dalby, S., 301.465.151488 INDEX O F AUTHORS’ NAMESDale, J., 201, 223, 337.Dalgarno, A., 19, 20, 26.Daly, J. J., 473.Daly, L. H., 36.Damen, H., 82.Dams, R., 413.Dance, D. F., 449, 450.Dancewicz, D., 434.Daniel, H., 265.Danieli, N., 255.Daniels, E. E., 300.Daniels, E. G., 301.Danielsen, J., 98.Danishefsky, S., 203.Dannley, R. L., 165.Danyluk, S. S., 76, 172.Dappen, G. M., 205, 238.Darling, S., 301.Darlow, 8. F., 457, 472.Da Rooge, M. A., 230,Das, J., 411.Das, M., 147.Das, T.P., 151.da Settimo, A., 277.Dasgupta, M., 278.Datar, D. S., 451.Dathe, W., 270.Dauben, H. J., jut., 113,Dauben, W. G., 197, 242,Daudel, R., 25, 27.Dautrevaux, M., 31 1.David, D. J., 438.David, S., 392.Davidson, E. R., 25.Davidson, N., 30, 48, 50,Davie, A. W., 477.Davies, A. G., 93.Davies, D. A. L., 339.Davies, D. I., 165, 231.Davies, R. F. B., 131.Davies, W. A. M., 298.Davis, B. T., 248.Davis, C. S., 281.Davis, D. R., 59, 67, 427,Davis, J. B., 68, 217.Davis, R. E., 85.Davison, A., 113, 117.Dawber, J. G., 153.Dawson, B., 22, 456.Dawson, J. B., 438.Dawson, J. W., 84.Dawson, T. L., 348.Day, A. C., 206.Day, R. A., jun., 438.Dayal, P., 398, 415.De, Anil K., 405.Deakin, W.A., 39.Dean, F. M., 276, 283.Dean, G. A., 400, 405.Dean, J., 347.Dean, J. A., 434, 405.323.156, 236.478.53, 234.441.Deana, A. A., 227, 228.Dearman, H. H.; 142, 152.Dearnaley, D. P., 406.Debabov, V. A., 375.Debo, A., 98.Decius, J. C., 44, 50.Deffner, G. G. J., 301, 368.DeFord, D. D., 410, 422,de Grandchamp-Chaudun,De Graw, J. I., 282.de Groot, M. S., 153.de Heer, J., 142.Dehl, R., 64.Dehm, H. C., 69, 114.Dehm, R. L., 433.Dehnicke, K., 93, 123.de Kowalewski, D. E., 73.Delahay, P., 419.de la Mare, P. B. D., 163,Delany, M. E., 29.Delaney, R., 320.Delasanta, A. C., 407.del Campillo, A., 353.del Carmen Asuncih, M.,de Ligny, C. L., 153.Delmau, J., 73.Delobelle, J., 254.Delsemme, A., 253.De Maine, M.M., 36.De Maine, P. A. D., 36.de Mayo, P., 242, 248, 259.Demerec, M., 386.Demole, E., 408.De More, W. B., 234.Demuth, E., 307.den Hertog, H. J., 167.Denney, D. B., 204, 215.Denning, P. H., 202.Deno, N. C., 162.Denot, E., 326.Dent, W. T., 109.Deorha, D. S., 276.De Puy, C. H., 175, 184,185, 186, 205, 238, 240,241.Derevitskaya, V. A., 341,343.de Ruggieri, P., 326.Desantis, W., 221.Desbarres, J., 421.Dessy, R. E., 108, 168, 169.de Stevens, G., 206.De Tar, D. F., 231.Deuel, H., 237.Deulofeu, V., 278, 333.Deuschel, G., 266.Dev, S., 253.Devaure, J., 41.de Villiers, J. P., 251.de Vries, A., 479.de Waard, A., 354.De Wald, H., 313.439.A., 336.184.433.Dewar, E. T., 343.Dewar, J.H., 300.Dewar, M. J. P., 142, 143,Dewey, R. S., 95, 201.Dewhurst, B. B., 323.Dey, A. K., 407, 416.Dhaneshwar, R. G., 442.Dhar, M. L., 287.Dhar, M. XI., 287.Dhein, R., 263.Dhont, J. H., 442.Diara, A., 257.Diassi, P. A., 291, 325.Dibeler, V. H., 450.Dickens, B., 114, 464.Dickens, P. G., 32, 33, 50,Dickerson, R. E., 317.Dickey, E. E., 289.Diehl, H., 425.Diehl, P., 55, 56, 65, 66, 73.Dietl, A., 264.Dietrich, B. F., 82.Dietrich, H., 306, 473.Dietrich, M. A., 100, 216,Dietz, L. A., 450.Dietz, R., 167.Dijkstra, G., 406.Dillier, M., 431.Dils, R., 365.Dihuzio, J. W., 120.Dimeler, G. R., 444.Dimroth, K., 203, 263, 276.Dincer, D., 325.Dinu, D., 233.Dinulescu, I. G., 233.Dion, H. W., 339.Di Sabato, G., 184.Disch, K.H., 243.Dismukes, J. P., 106.Di Somma, A. A., 301.Dittmer, D. C., 263.Dituri, F., 353.Dix, P. A., 272.Dixon, H. B. F., 315.Dixon, J. A., 66.Dixon, J. P., 420.Dixon, J. S., 315, 316.Dizabo, P., 38.Djerassi, C., 186, 187, 188,189, 193, 195, 196, 247,248, 252, 256, 257, 259,277, 282, 283, 287, 289,297, 299, 302, 305, 322,323, 324, 326, 334.144, 167.53.263.Doane, W. M., 349.Dobiasova, M., 304.Dobinson, B., 67, 273.Dobos, S., 433.Dodd, R . E., 36.Dodge, R. P., 124,232,465.Dodgson, K. S., 342, 351.Dodson, R. M., 325.Dolberg, U., 332INDEX OF AUTHORS’ NAMES 489Doering, W. von E., 179,Dohmann, K.-D., 125.Dolby, L. J., 196.Doleji, L., 252.Doleial, J., 402, 421, 422,Donaldson, J. D., 93.Donohue, J., 455, 460, 473,Donskaya, D.B., 85.Dopke, W., 294.Dorazil, L., 415.Dorfman, R. I., 335.Dorn, F. W., 80.Doty, P., 305, 367.Douglass, R. M., 122, 452.Dovell, F. S., 264.Down, J. L., 59.Downing, D. T., 218, 220.Downing, R. G., 153.Downs, A. J., 135.DOWS, D. A., 43.Dowson, B. A., 426.Doyle, D., 350.Doyle, J. R., 113, 119, 464.Doyle, R. R., 410.Drago, R. S., 75, 96.Drake, G. L., 348.Drake, G. W., 441.Drake, J. E., 91, 123.Dreeskamp, H., 59, 70.Drefahl, G., 203.Dreger, L. H., 194, 247.Dresdner, R. D., 94.Dressler, K., 43.Drewes, S. E., 422.Drews, H., 229.Dreyer, D. L., 283.Drickamer, H. G., 38.Dronov, A. P., 48.Druding, L. F., 121, 135.Drummond, D. W., 352.Dryden, H. L., jun., 201,Drysdale, G.R., 353.Drysdale, J. J., 213.Dubb, H. E., 56.Dubeck, M., 114, 116, 236.Ducker, J. W., 242.Dudek, G. D., 62.Dudek, G. O., 75.Diirselen, W., 428.Dufay, P., 332.Duff, R. E., 46, 48, 52.Duffey, D. C., 185.Duffy, R., 93.Dula,r, T., 413.Dunaevskaya, K. A., 401.Duncan, A. B. F., 27, 139.Duncan, J. L., 266, 439.Duncanson, L. A., 109.Duncanson, W. E., 11.Dunckley, G. G., 406.Dunell, B. A., 77.234, 238.445.475.Dragavtseva, N. A., 421.332.Dunham, J. M., 423.Dunitz, J. D., 113, 126,133, 197,464,465,469.Dunlap, L. B., 423.Dunn, M. S., 306.Dunn, W. G., 433.Dunstan, I., 82.Durante, M., 372.Duranti, D., 476.Durden, J. A., 262.Dutcher, J. D., 342.Dutta, N. L., 289.Dutta, P. C., 254.Dutta, S. N., 473.du Vigneaud, V., 314, 315.Dux, J.P., 410.Dvolaitzlry, M., 328.Dvoretzky, I., 178, 203.Dvornik, D., 298.Dvoryenkin, V. F., 459.Dweltz, N. E., 352, 479.Dwyer, F. P., 107, 129.Dyall, L. K., 41, 271.Dyer, J. R., 300.Dziomko, V. M., 401.Eaborn, C., 160, 161, 167.Eardley, S., 324.Earnshaw, A., 105.Ea,stman, R. H., 248.Eastoe, J. E., 304, 371.Eastwood, F. W., 311.Eaton, D. R., 691.Eaton, P., 246.Eberhard, L., 351.Eberle, L., 125.Eberle, M., 217.Ebersen, L., 74.Ebert, A. A., 450.Ebert, E., 126.Ebsworth, E. A. V., 90, 135.Eckart, C., 141.Eckerlin, P., 469.Eckstein, F., 340.Eckstein, M., 301.Eder, R. J., 231.Edmonds, P. D., 28.Edmundson, A. B., 317.Ednam, P., 302.Edward, J. T., 154, 193.Edwards, A.J., 31, 469.Edwards, D. A., 126.Edwards, J. O., 77.Edwards, J. W., 421.Edwards, 0. E., 298.Edwards, P. N., 292.Edwards, R. L., 272, 273.Edwards, R. T., 35.Edwards, T. E., 350.Eeckhaut, Z., 449.Effenberger, F., 172, 279.Ege, S. N., 219.Eggerer, H., 362.Eglington, G., 38, 41.Ehrenberger, F., 431.Ehrenson, S., 25.Ehrlich, G. G., 86.Ehrlich, P., 123.Ehrlichmann, W., 205.Eich, S., 394.Eichenberger, K., 279.Eilers, K. L., 240.Eisch, J., 208.Eischens, R. P., 44, 46.Eisenbrand, J., 434.Eisenbraun, E. J., 189,Eisenhauer, G., 100.Eisenstiidter, J., 422.Eisner, M., 78.Eistert, B., 273.Eiter, K., 216, 218.Elagroudi, Z. E., 267.Elbert, W., 403.Elderfield, R. C., 245.Eley, D. D., 87, 463.Elfstrom, M., 461.Elias, L., 53.Eliason, M.A., 26.Eliel, E. L., 180, 186, 196,Eliseeva, L. E., 108.El Khadem, H., 341.Elks, J., 324, 325.Elleman, D. D., 71.Ellinger, F. H., 460.Ellington, P. S., 41.Elliot, G., 434.Elliott, D. F., 313.Elliott, I. W., 278.Elliott, M., 248.Elliott, M. C., 448.Elliott, N., 456, 462.Elliott, R. G., 368.Ellis, B., 326.Ellison, A. H., 46.Ellison, F. O., 25, 139.Ellison, H. R., 107.Ellsworth, L. D., 428.Elmore, D. T., 302.Elmore, N. F., 258.Eloy, F., 269.El Sawi, M. M., 341.El-Shafei, Z. M., 341.Elvehjem, C. A., 394.Elvidge, J. A., 63, 157, 272.Elving, P. J., 421, 441.Emelbus, H. J., 98, 135.Emerson, M. J., 76.Emery, E. M., 450.Emmons, W. D., 204, 215.Emsley, J. W., 76.Emtage, P. R., 69.Enders, H., 374.End, L., 253.Endroi-Havas, A., 414.Eng, von W., 201.Engel, J., 370.Engel, L.L., 321.Engelbrecht, A., 101.Engelhard, N., 275.247, 252, 282.231, 247490 INDEX OF AUTHORS’ NAMESEngelsma, J. W., 159.England, B. D., 173.England, D. C., 100, 216,English, J., jun., 237.English, W. D., 83.Enk, E., 221.Entelis, S. G., 153.Enzell, C., 253, 256.Epple, G. V., 153.Epstein, P. S., 17.Epsztein, R., 211, 212.Ercoli, A., 327.Erdey, L., 452.Erdtman, H., 253,256,282.Erickson, R. E., 39, 253.Erlanger, B. F., 307.Emi, A. D. T., 276.Emede, L. A., 225,226,227.Ertel, H., 204.Eschenmoser, A., 299.Esteve, R. M., 155.Estramareix, B., 392.Ettinger, R., 94.Ettre, L. S., 410.Eucken, A., 30.Euler, H. D., 98.Euler, R.D., 94.Eusebi, A. J., 394.Eusef, M., 414.Evans, D. F., 57, 72.Evans, H. T., 455, 466.Evans, R. H., 335.Evans, R. S., 409.Ewing, G. E., 43.Eyring, H., 141, 188.240, 263.Fabian, W., 171.Fabricand, B. P., 76.Fackler, J. P., jun., 132.Fahmy, A. R., 304.Fahrenfort, J., 45.Fahrenholtz, K., 282.Faigle, H., 217.Fainberg, A. H., 173.FajkolS, J., 323, 335.Fales, H. M., 285, 294, 295,Falk, J. E., 408.Fallat, S., 107.Fanshawe, W. J., 238.Farag, M. S., 473.Fadow, M. W., 96.Farr, J. D., 460.Farrington, P. S., 423.Farrow, R. N. P., 434.Fasella, P., 395.Fasman, G. D., 302.Fassel, V. A., 433.Fassnacht, J. H., 235.Fateley, W. G., 43.Fava, A., 176.Favier, P., 164Favini, G., 145.Favorskaya, I. A., 431.296.Fawcett, F. S., 225.Fearm, J.E., 224.Federov, P. I., 130.Fedorova, E. F., 430.Feigl, F., 402, 403.Felauer, E. E., 217.Feldhoff, M., 340.Feldkimel, M., 118, 237.Feldmam, L. I., 335.Feltz, A., 124.Feng, M. S., 181.Fern, E., 129.Fenton, A. J., 425.Ferguson, G., 249,471,479.Ferguson, L. T., 374.Ferguson, W. C., 450, 451.Fern, A. S., 348.Fernelius, W. C., 104.Ferrari, A., 470.Ferrari, C., 326.Ferrer Pi, P., 438.Fernier, R. J., 335, 340.Fessenden, 5. S., 87.Fessenden, R., 87, 175.Fessler, J. H., 367.FBtizon, M., 254.Fetzer, U., 310.Feuer, H., 210, 216.Fialkov, Y. A., 91.Fichtel, K., 112.Fidler, D. A., 198.Field, G. F., 281.Field, L., 203.Field, N. D., 270.Fields, E. K., 229.Fieser, L. F., 326.Fife, T.H., 180.Fife, W. K., 159.Fifield, F. W., 447.Figgis, B. N., 105.Fijalkowski, J., 433.Filbey, A. H., 114, 236.Fildes, J. E., 431.Fildes, P., 383.Filiminov, V., 44.Filler, R., 75.Finar, I. L., 300.Finch, N., 195.Finckenor, L. E., 327.Findlay, D., 320.Fine, D. A., 129.Fine, J. M., 408.Finegold, H., 67.Fink, W., 90, 216.Finnegan, R. A., 245, 257,Firsching, F. H., 413.Firth, W. C., jun., 206.Fiiar, C., 444.Fischer, A., 162.Fischer, E. O., 81, 109, 112,113, 114, 115, 117, 118,157, 236, 237, 464.282.Fischer, H., 231.Fischer, H. D., 85.Fischer, H.-G., 233.Fischer, I., 141.Fischer, J., 100.Fischer, R. B., 412.Fischer, R. D., 114, 118.Fischer-Hjalmars, I., 25.Fischmann, E., 474.Fisel, S., 407.Fish, A., 410.Fish, R.W., 227.Fisher, D. J., 422, 425, 441.Fisher, P. J., 469.Fishman, E., 38.Fishman, J., 323.Fishman, L., 373.Fishman, M. M., 349.Fishman, S., 403.Fitches, M. J. H., 177.Fitton, P., 235.Fitzsimmons, B. W., 97.Fixman, M., 63, 151.Flaig, W., 237.Flanigan, D. A., 421.Fleischer, H., 144.Flek, J., 443.Fleming, I., 210.Fleming, I. D., 349.Fleming, J. E., 466.Flengas, S. N., 469.Fletcher, H. G., jun., 343,Fletcher, J. M., 111.Fletcher, T. L., 209.Flis, I. E., 426.Flodin, P., 346.Flood, S. H., 161.Floret, A., 431.Flournoy, J. M., 154.Flowers, H. M., 219.Pluck, E., 98.FojtovB, V., 430.Foley, H. M., 17.Folk, J. E., 317.Folkers, K., 217.Foltz, C. M., 303.Fondy, T. P., 69.Fonken, G.J., 243, 324.Fontanella, L., 206, 262.Fontell, K., 219.Foote, J. L., 230.Fordemwalt, J. N., 102.Ford-Smith, M. H., 107,Forel, M. T., 42.Foreman, J. K., 435.Formica, J. V., 360.Forneris, R., 102.Forrester, J. D., 454.Forsander, O., 394, 406.ForsBn, S., 64, 74, 253,Forsthoff, L., 340.Fortuin, J. M. H., 424.Fosdeck, L. S., 304.Foss, J. G., 305.Foster, A. B., 67, 273, 337,345.179.340.340, 352INDEX OF AUTHORS’ NAMES 491Foster, A. G., 412.Foster, G., 107, 203.Foster, J. F., 348.Foster, J. M., 28, 139.Foster, R., 84, 220.Foster, W. E., 205.Fowden, L., 300.Fowles, G. W. A., 79, 123,Fox, G. F., 208.Fox, I. R., 164.Fox, J. R., 177.Fox, L., 22.Fox, W. B., 85.Foxley, G. H., 402.Fraenkel, G., 65, 151.Fraenkel, G.K., 152.Fraenkel-Conrat, H., 319.Fraga, S., 26.Franc, J., 407.Francetid, D., 192, 221.Franchevici, H., 407.Francis, A. W., 171.Francis, S. A., 46.Franck, R. W., 325.Franpois, P., 145.Franconi, C., 17.Frank, C. E., 205.Frank, F. C., 460.Frank, R. W., 296.Franken, J., 246.Franklin, J. L., 148.Frankus, E., 200.Franz, G., 307.Franz, R. A., 207.Franzen, V., 205, 235.Franzen, W., 171.Franzus, B., 223.Fraser, R. R., 59, 60, 158.Fraser, R. T. M., 106.Fraser-Reid, B., 338.Frass, W., 213.Fray, G. I., 218.Frazer, B. C., 456, 457.Frazer, J. W., 94.Fredga, A., 186.Freedman, F., 48.Freedman, H. H., 116, 232.Freegarde, M., 440.Freeman, A. J., 13, 22, 26,Freeman, H. C., 457, 467.Freeman, J.P., 94, 210.Freeman, P. R., 277.Freeman, R., 57, 73.Freenor, F. J., 175.Freiberg, L. A., 323.Freiser, H., 404.French, D., 349.Freni, M., 120, 127.Freudenberg, K., 237, 345.Freund, I., 349.Freure, R. J., 217.Frey, D. A., 205, 211.Frey, H. M., 178.Fridrichsons, J., 478.124, 126.455.Friebolin, H., 67.Fried, J., 325.Friedel, R. A., 223.Friedman, L., 179,206,213,216, 238, 242.Friedrich, K., 205.Fries, R. J., 128.Frisch, H. L., 191.Frisch, M. A., 194, 247.Fritchie, C. J., 249, 479.Fritz, G., 88.Fritz, H. P., 80, 113, 114,Froman, A., 10.Frostling, H., 190.Frush, H. L., 336.Frydman, B., 278.Frye, C. L., 91, 175.Frye, H., 428.Fueki, K., 45.Fueno, T., 8, 142.Fiirst, A., 332.Fujimoto, K., 345.Fujino, A., 287.Fujino, M., 301.Fujita, Y, 301.Fujitani, K., 92.Fujiwara, M., 211.Fujiwara, S., 56, 59, 74,Fukui, K., 66, 147, 148,Fuller, M.W., 153.Fuller, N. A., 182.Funk, H., 126.Furberg, S., 335.Furcht, G., 125.Furman, N. H., 425.Furukawa, C., 430.Furukawa, K., 215.Furukawa, S., 253.Furuta, S., 193.Fuson, N., 37, 38, 40, 42.Fuson, R . C., 229.Futrell, J. H., 192.Fyfe, W. I., 48.117.151.158.Gabarino, J. A., 287.Giinshirt, K. H., 255.Gilumann, E., 348.Gagnaire, D., 266.Gaiffe, A., 205.Gaillard, B. D. E., 346.Gainer, H., 167.Gaj, B. J., 208.Gajek, K., 242.Galatry, L., 39, 42.Galbraith, A., 282.Gale, L. H., 169, 247.Galinos, A. G., 87.Gallardo, R., 25.Gallop, P. M., 308, 373, 374.Ganchoff, J., 427.Gandolfi, C., 326.Ganguly, A.K., 258.Ganguly, J., 360, 364.Gaoni, Y., 205,234.Gapp, F., 304.Garcia-Fernandez, H., 101.Gardi, R., 327.Gardiner, W. C., 47, 51.Gardner, A. W., 446.Gardner, J. N., 214.Grtrdner, P. D., 225, 228,Gardner, R. A., 45.Garg, C. P., 203, 242.Garland, C. W., 45.Garland, T. J., 435.Garn, P. D., 451.Garner, C. S., 126.Garnett, J. L., 56.Garratt, S., 289.Garrett, A. B., 169.Garvan, F. L., 107, 129.Gaslini, F., 420.Gaspar, R., 23, 26.GaspariE, J., 407.Gaspert, B., 190.Gassier, J., 75.Gastilovich, E. A., 36.Gastmeier, G., 89.Gaston, L. K., 169.Gatzke, A. L., 175.Gauer, J. N., 341.Gauthier, G., 31.Gavat, M., 274.Gavilanes, C. R., 332.Gamon, O., 69.Gaydon, A. G., 28, 46, 50.Gehring-Muller, R., 317.Geiger, H., 245.Geiseler, G., 221.Geisenfelder, H., 166.Geiss, F., 273.Geissel, D., 219.Geissman, T.A., 288.Geist, K., 263.Geller, L. E., 196, 209, 329.Geller, S., 455.Gendre, T., 321.Gensler, W. J., 219.Gentles, M. J., 327, 335.George, T., 289.Gerber, G. B., 378.Gerdil, R., 457.Gergely, J., 68.Gerig, J. T., 164.Gerken, R., 125.Gerrard, W., 75.Gerstenberg, B., 124.Gervais, H.-P., 248.Gestlom, B., 264.Gething, B., 224.Getoff, N., 446.Gewald, K., 270.Gewanter, H. L., 213.Ghatak, U. R., 200.Ghirardelli, R. G., 170.Ghose, S., 476.Ghuysen, J. M., 350.252492 INDEX OF AUTHORS’ NAMESGiacomello, G., 476.Gianni, F., 433.Giannini, U., 86.Gibbins, S. G., 66.Gibian, H., 310.Gibson, C.G., 249.Gibson, D. M., 357, 358.Gibson, L. E., 450.Gibson, M., 254.Gibson, M. S., 179.Gibson, N. A., 428.Gier, T. E., 95.Gierst, L., 419.Giesecke, W., 410.Giessner-Prettri, C., 73, 75.Giglio, M., 470.Gilbert, B., 282.Gilbert, G. A., 348.Gilbert, R., 455.Gilbert, T. L., 149.Gill, N. S., 104, 127, 128.Gillam, A. E., 248.Gillam, I. C., 340.Gillard, R. D., 107, 191.Gillespie, R. J., 79, 100,Gilman, H., 88, 208.Gilmore, W. F., 241.Ginsburg, D., 194.Giorgi, A. L., 460.Giraitis, A. P., 108.Giroud, A.-M., 328.Gish, D. T., 319.Givens, W. G., 53.Giza, C. A., 305.Gladner, J. A., 317.Glaid, A. J., 69.Glasel, J. A., 71.Glass, B., 383.Glass, I. I., 28.Glass, J. R., 423, 425.Glass, M. A. W., 188, 191,Glaze, W., 80, 171.Glaze, W.H., 208.Glazer, A. N., 320.Glazer, Z. T., 342.Gleinig, H., 214.Glemser, O., 94, 96.Glen, G. L., 79, 124, 466.Glenat, R., 213.Glick, H. S., 46.Glick, R. E., 63, 86.Gliemann, G., 139.Glimcher, M. J., 378.Glockling, F., 94.Gloersen, P., 48.Gloor, U., 217.Glover, C. A., 400.Glover, M., 431.Glushkova, V. P., 472.Glusker, J. P., 479.Gmelin, R., 301.Gnoj, O., 209, 325, 326.Gnutzmann, G., 80.Godat, J.-P., 403.240.193.Godfrey, L. E. A., 270.Godin, P. J., 283.Goebler, 0. H., 388.Goedder, H. W., 396.Goeders, C. N., 185.Goedkoop, J. A., 460.Goggel, K. H., 396.Goerdeler, J., 270, 306.Goering, H. L., 174, 175,Gorlich, P., 399.Gotz, R., 123.Goetze, W., 98.Gold, V., 153, 159, 160,.165,Goldberg, I.H., 219.Goldberg, M., 403.Goldberg, M. W., 219.Goldberg, S., 76.Golden, J. H., 208.Golden, J. T., 159.Golden, S., 44.Goldfarb, T. D., 43.Gol’dfarb, Y. I., 186.Goldin, A. S., 405.Golding, R. M., 101.Goldish, E., 460, 473.Goldman, D. S., 353.Goldman, N. L., 207.Goldschmid, H. R., 339,Goldschmidt, S., 307.Goldstein, D., 402.Goldstein, G., 405, 418.Goldstein, I. J., 349.Goldstein, J. A., 70.Goldstein, J. H., 61, 64, 66,Goldyn, J., 407.Golebiewski, A., 149.Gompper, R., 272.Gonalez, A. G., 258.Goodfriend, P. L., 27, 139.Goodgame, D. M. L., 130,Goodgame, M., 130.Goodings, D. A., 13.Goodman, J. J., 329.Goodman, L., 142,146,344.Goodwin, T. W., 390, 392.Goosen, A. L., 294.Gopinath, K.W., 256.Gordon, G., 122.Gordon, I,., 412, 413.Gordon, M., 385.Gordon, S., 72.Gordy, W., 152.Gorin, P. A. J., 350.Goring, D. A. I., 352.Gorman, M., 292.Gorovits, M. B., 333.Gortsema, F. P., 129.Goto, T., 326.Gottbrath, J. A., 85.Gottschalk, A., 321.Goubeau, J., 83, 85, 90, 96.176.176, 182.346.68, 265.133.Gough, S. T. D., 210.Gould, E. S., 475.Gould, R. D., 53.Goulding, K. J., 350.Goutarel, R., 290, 292.Gouterman, M., 146, 153.Gouverneur, P., 429.Govett, G. J. S., 436.Govindachari, T. R., 256.Gowda, H. S., 411.Gowers, D. S., 220.Graber, K., 409.Grace, J. A., 181.Gracheva, E. P., 36.Graddon, D. P., 103.Griinacher, I., 55, 74, 75.Grafnetterovti, J., 422.Graham, W., 326.Graire, A., 413.Granath, K.A., 346.Grange, P., 36.Grant, D., 342.Grant, D. M., 57.Grant, N. H., 367.Grant, P. K., 255.Grassmann, W., 370, 371,372, 374, 375, 376.Gratzer, W. B., 305.Gravitt, J. C., 31, 32.Gray, B. F., 20.Gray, D. O., 300.Gray, H. B., 104.Gray, M. Y., 86.Graybill, B. M., 81, 82.Grdenid, D., 93, 466, 469.Green, B., 200.Green, D. E., 353, 358.Green, G. F. H., 324.Green, J. H. S., 262.Green, M., 79, 142, 146.Green, M. L. H., 69, 112,Green, N. M., 371.Green, S. I. E., 80.Greenbaum, M. A., 192.Greendale, A. E., 441.Greene, E. F., 46, 49.Greenfield, B. F., 94.Greenfield, S., 419,422,431.Greenspan, G., 335.Greenspan, M., 29.Greenstein, J. P., 300, 307.Greenwood, C. T., 349.Greenwood, H. H., 147,148.Gregorian, R.S., 227.Gregory, G. I., 324.Gregory, K. W., 126, 469.Gremm, J., 111.Grenville-Wells, H. J., 455.Greull, G., 353, 395.Greville, G. D., 353.Grewe, R., 215.Griaznov, G., 198.Gribova, E. A., 418.Gribova, I. A., 97.Griffin, G. W., 215, 233.117INDEX OF AUTHORS' NAMES 493Griffin, R. N., 155.Griffing, V., 142.Griffith, J. S., 103.Grif'fith, W. P., 111, 112.Griffiths, J. E., 91.Grim, S. O., 89, 95.Grimes, R., 82, 461.Grisebach, H., 282.Grisley, D. W., 41.Grisley, D. W., jun., 207.Griswold, E., 130.Grob, C. A., 278.Grobe, J., 88.Groen, S. H., 212.Gronowitz, S., 56, 61, 68,190, 264.Gros, C., 314, 316.Gross, D., 408.Gross, E., 303.Gross, J., 367,368, 369,378.Grosse, A. V., 99.Grosse-Ruyken, H., 89.Grossman, R .F., 284.Groth, P., 471.Groulade, J., 408.Grove, E. L., 428.Grove, J. F., 257, 260.Grovenstein, E., 171, 211,Grubert, H., 237.Gruen, D. M., 124.Gruen, H., 197.Griinanger, P., 268.Griindemann, E., 206, 216.Griine, A., 398.Grutzmacher, H.-F., 304.Grundmann, C., 97.Grundschober, F., 346.Grunwald, E., 76.GuBrin, G., 421.Guermont, J.-P., 21 1.Guiochon, G., 452.Guirgiu, D., 134.Guiseley, K. B., 341.Gunsalus, I. C., 385.Gunstone, F. D., 217.Gupta, G. S., 253.Gupta, P. K., 407.Gupta, Y. K., 414.Gurin, S., 353, 373.Gusev, S. I., 401.Gustavson, K. H., 368.Gut, M., 335.Gut, R., 124.Gutenmann, W. H., 429.Guthrie, J. D., 348.Guthrie, R., 391.Gutmann, V., 90, 96, 123,Gutowsky, H. S., 57, 61,Gutowsky, S., 60.Gutsche, W., 123, 469.Gutterson, M., 426.Guttmann, S., 99.Guy, R.G., 109, 118, 230.224.444.70, 77, 130, 150, 152.Gyaw, M. O., 351.Gyenes, I., 412.Gfn Li., 425.Gyorgy, P., 355.Haack, E., 332.Haaf, F., 267.Haag, W. O., 204.Haage, W., 109.Haahti, E. 0. A., 322.Haake, P. C., 183.Haarhoff, P. C., 406.Haarstad, V. B., 278.Haas, H. J., 339, 342.Haase, B., 167.Habeeb, A. F. S. A,, 302.Haber, J., 104.Haber, R. G., 247.Haberfield, P., 170.Haberman, N., 412.Hadley, W. B., 129.Hadwick, T., 181.Haeberle, H., 96.Kaeuser, J., 256.Hafner, K., 156.Hafner, W., 236.Hagihara, N., 211, 232.Hagstrom, S., 25.Haguenauer - Castro, D.,Hahn, E. L., 151.Hahn, R. B., 404, 449.Haim, A., 129.Haissinsky, M., 121.Hai Won Chang, 239.Hale, C.C., 435.Halevi, E. A., 145, 155, 156,Halfhide, P. F., 422.Hall, A. N., 176.Hall, C. E., 367.Hall, D., 132, 468.Hall, G. G., 10, 20, 22, 138,Hall, L. C., 421.Hall, L. D., 344.Hall, M. E., 443.Hall, N. D., 223.Hall, S. P., 326.Hall, W. D., 181.Hallam, H. E., 37, 40.Halpern, J., 69, 87, 110,Halsall, T. G., 248, 258,Ham, N. S., 143.Hamamoto, K., 333.Hamana, M., 167.Hamano, H., 148.Hambling, J. K., 165, 231.Hambly, A. N., 184.Hameka, H. F., 19.Hamer, N. K., 128.Hamied, Y. K., 241.Hamilton, J. A., 292, 478.402, 403.170145, 152.112, 197, 211.259, 323.Hamilton, J. B., 419, 426,Hamilton, P. B., 304.Hamilton, W. C., 462, 472.Hammerschmidt, W., 334.Hammond, G.S., 178.Hamor, T. A., 249, 260,292, 478, 479.Hampel, B., 324.Hampel, O., 270.Hance, A. B., 450.Handler, G. S., 169.Handler, P., 395.Handley, T. H., 405.Hands, A. R., 248.Handy, C. T., 211, 223.Hanic, F., 467.Hanicovh, K., 467.Hama, R., 258.Hanna, S. B., 179.Hannan, R. B., 45.Harnig, K., 370, 371, 377.Hanrahan, L. R., 450.Hans, A., 410.Hanselman, R. B., 423.Hansen, H. J. M., 406.Hansen, J., 279.Hansen, R. L., 169, 246.Hansen-Nygaard, L., 144,Hanson, A. W., 477.Hansson, A., 85.Han Tai, 438.Happe, J. A., 59, 73.Happold, F. C., 388.Harada, K., 289.Haran, E. N., 434.Hardegger, E., 283.Harder, R. J., 213.Harding, M. M., 469.Hardisson, A., 68, 216.Hardy, A., 123.Hardy, C. J., 94.Hardy, F. R.F., 410.Hare, J. B., 343.Hargitay, B., 337.Harington, C. R., 392.Harkness, A. C., 87, 110.Harkness, R. D., 367, 378.Harley-Mason, J., 68, 210.Harman, A. B., 85.Ha.rman, K. M., 85.Harmon, D. F., 105.Harrap, B. S., 305.Harrar, J. E., 441.Harrell, R. W., 146.Harrelson, D. H., 84.Harrington, R. E., 34.Harrington, W. F., 369,Harris, A. P., 178.Harris, B. W., 208, 216.Harris, C. M., 133, 134,Harris, D. L., 390.Harris, G. M., 103, 130.429.166.376.468494 INDEX OF AUTHORS’ NAMESHarris, G. S., 99.Harris, J. F., 407.Harris, J. I., 315, 319.Harris, M. M., 190.Harris, R. K., 66, 193,Harris, R. S., 355.Harris, W. E., 106.Harrison, H., 49.Harrison, W. W., 422.Harrod, J. F., 112, 197.Hart, H., 227.Hart, M.G. R., 437.Harteck, P., 53.Hartley, G. S., 399.Hartman, P. E., 386.Hartman, Z., 386.Hartmann, H., 139, 142,Hartree, D. R., 11.Harvey, D. R., 163.Harvey, L. G., 435.Hary, J., 125.Haschka, G., 98.Hashimoto, Y., 258.Haslam, E., 237.Haslam, J., 410, 419, 425,Haslewood, G. A. D., 334.Hass, D., 99.Hassan, M., 163.Haasel, O., 102, 463, 471.Hasspacher, K., 310.Hastings, J., 456, 462.Haszeldine, R. N., 82, 101,Hatch, L. F., 221.Hathaway, B. J., 105, 133.Hathaway, C., 159.Hato, H., 66.Hatt, B. A., 453.Hatt, H. H., 214.Hatton, J. V., 73.Hattori, S., 66.Hattwig, H., 100.Haubenstock, H., 180, 196.Haug, A., 350.Hauge, J. G., 358.Hauptman, H., 454.Hauser, C. R., 207, 264.Hauser, T. R., 403.Hausmann, E., 378.Hausser, J.W., 205, 238.Havinga, E. E., 101.Havii., J., 420.Haworth, R. D., 237.Hawrylyshyn, M., 408.Hawthorne, J. O., 205.Hawthorne, M. F., 81, 82,84, 86, 200, 213.Hayakawa, S., 335.Hayano, M., 335.Hayter, R. G., 120.Hayward, T. H. J., 147.Hazebroek, H. F., 45.Hazel, J. F., 442.281.220.426, 429, 432.224.Heal, H. G., 95, 101.Heath, C. E., 46.Heaton, B. G., 244.Heaton, F. W., 438.H6bert, N. C., 199.Heck, R. F., 114, 119,Hecker, E., 220.Hedberg, K., 98, 477.Heeschen, J. P., 64.Heffernan, M. L., 62, 144,Heicklen, J., 39.Heilmann, R., 213.Heilmayer, P., 90.Heinecke, K., 111.Heinemann, A., 98.Helbig, W., 401.Hele, P., 353, 354.Helf, S., 450.Helferich, B., 263, 340.Helfferich, F., 409.Helgorsky, J., 126.Heller, M.S., 331.Hellman, H., 228.Hellman, N. N., 345.Hellmann, H., 269.Helmkamp, G. K., 191.Hely Hutchinson, M., 131.Henbest, H. B., 202, 203,Henderson, L. J., 56.Henderson, M.C., 31.Henderson, M. G., 20.Hendrickson, J. B., 194,Hendrickson, J. G., 221.Hendrickson, Y. G., 197.Henn, D. E., 132, 466.Hennart, C,. 417, 431.Henneberg, D., 82.Hennion, G. F., 200, 212.Heppolette, R. L., 156.Herberg, R. T., 449.Herberich, G. E., 236.Herbst, D., 193.Herbst, P., 214.Herget, C., 108Hezrnhnek, S., 321, 324.Hermann, R. B., 230.Hernandez, R., 406.Hernandez, R., jun., 406.Herndon, W. C., 155, 185.Herout, V., 251, 252.Herr, W., 127.Herries, D. G., 320.Herringshaw, J. F., 400,Herrington, J., 446.Herrmann, M., 444.Hershberg, E.B., 327.Hertz, H. G., 76.Hertzberg, A., 46.Herwig, W., 223.Herz, W., 253, 259.Herzberg, G., 16, 145.236.158.241, 324.209, 263, 291.405, 422.Herzfeld, K. F., 28.Herzog, H. L., 327, 335.Heslop, R. B., 412.Hess, D. C., 450.Hesse, M., 293, 478.Hetman, J. S., 445.Heusler, K., 327, 330.Hewitt, G. C., 410.Hexter, R. M., 43.Hey, D. H., 165, 208, 209,Heyding, R. D., 128.Heyn, A. H. A., 413.Heyns, K., 304, 338, 373,Hichens, M., 342.Hickman, C. W., 101.Hieber, W., 108, 109, 111,Hietala, P. K., 301.Higginson, W. C. E., 131,Highberger, J. H., 368.Highet, P. F., 299.Highet, R. J., 294, 299.Hijikata, K., 26, 153.Hikino, H., 253.Hilderbrand, R. P., 251.Hileman, J. C., 108.Hill, A.G., 434.Hill, E. A., 117, 157, 236.Hill, J. A., 258.Hill, R. J., 317.Hill, R. K., 186.Hill, R. L., 320.Hilschmann, N., 317.Hilse, K., 317.Hiltebrand, H., 293, 478.Himes, J. B., 407.Himoe, A., 163.Hincky, J., 241.Hine, J., 170.Hinkler, K., 467.Hinman, J. W., 301.Hinman, R. L., 277.Hinterberger, H., 248.Hinton, J. F., 426.Hirai, S., 331.Hirase, S., 350, 351.Hirata, Y., 257, 273.Hiroike, E., 59, 150.Hirokawa, S., 472, 476.Hirota, K., 45, 70.Him, C. H. W., 317, 320.Hirsch, A., 403.Hirschberg, A., 167.Hirschfelder, J. O., 24, 26.Hirst, E. L., 350.Hiskey, R. G., 221.Hitomi, H., 342.Hitoshi Kamada, 433.Hoar, T. P., 423.Hoard, J. L., 79, 124, 127,Hoare, M. fb., 34.Hobom, G., 317.216, 231.376.119.468.128, 466Hocheneggar, M., 430.Hock, A.A,, 465.Hockett, R. S., 339.Hodge, A. J., 368, 371.Hodge, J. E., 346.Hodge, N., 121.Hodgkin, D. C., 473, 478,Hodson, H., 292.Hodson, H. F., 478.Hodson, J. F., 292.Hoehn, H. H., 69, 114,Hohne, K., 100.Hohr, L., 410.Hoelzel, C. B., 203.Horl, E. M., 460.Horrnann, H., 374,375,376.Horfeldt, A.-B., 264.Hofer, W., 309.Hoffer, M., 68.Hoffhan, R. A., 56, 60, 61,Hoffmann, E.-G., 156, 251.Hoffmann, H., 204.Hofmann, K., 306,315,316.Hofmann, R. A., 264.Hofmann, U., 374.Hoh, G., 117.Hoijtink, G. J., 146, 152.Hoji, K., 332.Hojo, M., 176.Hojvat, N. L., 142.Holah, D. G., 133.Holden, K. G., 288.Holden, M. P., 183.Holder, D. W., 47.Holeygovsk9, V., 304, 320.Holker, J.R., 349.Holker, J. P. E., 323.Holland, J. M., 181.Holliday, A. K., 85, 93.Hollingshead, S., 176.Ho116, J., 348.Holloway, J. T., 446.Holm, M. J., 341.Holm, R. H., 75.Holman, R. T., 218, 219.Holmes, J. R., 59, 62.Holmes, R., 31.Holmes, R. R., 96.Holmes, W. S., 98.Holm-Jensen, I., 419.Holmlund, C. E., 335.Holness, N. J., 180.Holst, A., 306.Holt, A., 342.Holt, N. B., 336.Holub, M., 252.Holubek, J., 324.Holzer, H., 396.Homberg, O., 205.Homer, J., 67, 273.Honeycutt, J. B., 82.Honeyman, J., 349.Honzl, J., 310.480.236.64, 68.INDEX OF AUTHORS’ NAB:Hood, G. C., 76.Hoogendonk, W. P., 451.Hoogzand, C., 11 6,222,223.Hoop, G. M., 230.Hooper, H. O., 151.Hooton, K. A., 177.Hoover, F. W., 211, 223.Hope, D.B., 315.Hope, €I., 102, 463.Hopff, H., 225, 242.Hopkins, C. Y., 218.Hoppe, R., 121, 127, 135.Hopwood, S. L., 226.Hordvik, A., 335.Horeau, A., 323.Horii, S., 342.Horler, D. F., 237.Horn, P., 476.Home, R. W., 350.Homer, L., 204.Hornig, D. F., 48.Horning, E. C., 322, 335.Horning, H. C., 203.Horning, M. G., 218, 364.Horsfield, A., 94.Horton, E. W., 313.Horton, K., 94.Hoiiala, J., 425.Hosanky, N., 299.Hoshino, R., 76.Hoshino, T., 220.Hoskins, B. F., 133, 468.Hospital, M., 474.Hoste, J., 413, 447, 449.Hough, L., 340, 342, 343,House, D. A., 131.House, H. O., 241.Hoverath, A., 430.How, M. J., ,342.Howard, H. E., 450, 451.Howard, W. L., 197.Howell, K. M., 19.Howells, D. J., 392.Howick, L.C., 413.Howk, B. W., 114, 236.Hoyland, J. R., 142, 146.Hoyt, J. M., 226.Hrutfiord, B. F., 285.Huba, F., 212.Hubbard, W. N., 194, 247.Huber, K., 125.Huber, W., 126.Huber-Buser, E., 197.Hubert, A. J., 337.Hubiski, W., 444.Hudec, J., 231, 233, 237,Hudson, G. H., 32.Hudson, R. F., 181.Hiibel, W., 113, 116, 223,Hubner, K., 283.Hiibner, L., 96.Huckel, W., 241.Hiigel, M.-F., 218.344.240, 246.232, 284.ES 495Hiinig, S., 201, 283.Huggins, D. K., 108, 117.Huggins, M. L., 375.Hughes, D. W., 276.Hughes, E. D., 159, 162,Hughes, E. W., 98, 457,Huguenin, R. L., 314, 315.Hui, W. H., 258.Huisgen, R., 269, 270.Hume, D. N., 440.Humiec, F. S., 97.Humphrey, R. E., 39.Huneck, S., 259.Hunt, D. M., 177.Hunt, J.P., 104.Hunter, J. V., 399.Huong, P. V., 40, 42.Hurle, I. R., 28, 46, 50.Hurle, J., 28.Hurley, A. C., 26, 139, 140.Hurst, J. J., 243.Hutchinson, D. W., 237.Hutchinson, J. H., 119.Hutchison, C. A., 153.Hutchison, W. C., 399.Hutson, D. H., 336, 337,Huynh, C., 324.Hylleraas, E. A., 15, 141.Hyman, H. H., 98, 122.Hyne, J. B., 74.167, 168.460, 477.H-tedt, H.-H., 183.339, 345.Iagupolskii, L. M., 66.Iball, J., 474.Ibbotson, R. N., 408.Ibers, J. A., 455, 456,Mand, D. C., 203.Igarashi, K., 333.Igarashi, M., 261.Ignczak, M., 422.I’Haya, Y., 146.Ihrman, K. G., 115.Iitaka, Y., 479.Ikekawa, K., 325.Ikekawa, N., 322.Iliceto, A., 176.Im, Y. A., 107.Imagawa, T., 253.Imamura, A., 147.Imanishi, S., 40, 41.Immer, H., 330.Impastato, F.J., 115, 193.Inagami, K., 381.Inamasu, S., 192, 238.Ingold, C.K. (Sir), 162,Ingram, G., 428, 429, 430.Ingram, V. M., 317.Inoue, M., 301.Inouye, H., 315.Inouye, Y., 192, 238.470.167, 168496 INDEX OF AUTHORS’ NAMESInskeep, R. G., 126.Intorre, B. I., 425.Inubushi, Y., 296.Inukai, K., 66.Inuzuka, K., 40, 41.Ionov, V. I., 121.Ipata, P. L., 407.Ireland, R. E., 254, 255,Ironside, C. T., 144.Irreverre, F., 320.Irvine, V. C., 426.Irving, H., 107, 191.Irving, J. T., 372, 373.Isaeba, Z. G., 68.Isaks, M., 240.Isbell, H. S., 335, 336, 337.Iseli, E., 333.Iselin, B., 305, 306, 307.Isensee, R. W., 166.Ishii, H., 289, 333.Ishikawa, M., 277.Iskander, Y., 179.Isler, O., 217.Islip, P. J., 213, 219.Isobe, T., 66.Israelstam, S.S., 282.Issleib, K., 98.Ito, H., 476.Ito, K., 63, 66.Ito, M., 40, 41.Itoh, J., 70.Itoh, T., 141.Ivanov-Emin, B. N., 121.Iveten, J. L., 209.Iwamoto, R. T., 441.Iwasa, J., 257.410.Jackman, L. M., 58, 63, 68,71, 157, 216, 217, 260,272, 283, 293, 478.Jackson, A. H., 68, 278,284.Jackson, D. S., 367, 368,378.Jackson, H., 401.Jackson, J. A., 76.Jackson, S. F., 378.Jacob, M. I., 357.Jacobs, A. L., 301.Jacobs, J., 139.Jacobs, S., 367.Jacobs, T. L., 215.Jacobson, M., 220.Jacobson, R. A., 454.Jacox, M. E., 43.Jacques, J., 328.Jager, H., 169, 333.Jaeger, R. H., 218.Jaggi, H., 470.Jain, B. D., 411.Jakusik, E. R., 92.James, A. T., 410.James, B. R., 104, 112,197, 211.James, C.G., 50.James, H. M., 16, 24.Jamieson, D. R., 421.Jamieson, N. C., 344.Janata, J., 422.Jander, J., 102.Janes, N. F., 282.Janjic, D., 73.Jankowski, S. J., 404.Jam, I<., 261.Janot, M. M., 290, 292.Janson, J., 337.Janssen, N. G., 419.Janz, G. J., 172.Jaquenoud, P.-A., 313, 316.Jaques, D., 177.Jaques, R., 313.Jarboe, C. H., 287.Jardetzky, C. D., 68.Jarvie, A. W. P., 88.Jarvis, D., 313.Jarvis, J. A. J., 467.Jaselskis, B., 128.Jaunin, R., 403.Jauregui-Adell, J., 321.Jeanloz, D. A., 342.Jeanloz, R. W., 342.Jeffers, W., 81.Jeffery, P. G., 432.Jeffery, W. S., 428.Jeffrey, G. A., 462, 476.Jeffs, A. R., 410.Jeffs, P. W., 299.Jeger, O., 297, 330, 331.Jellinek, A., 425.Jellinek, F., 126, 157, 269,Jellinek, O., 402.Jencks, W.C., 181.Jencks, W. P., 182, 183,Jenik, J., 416.Jenkins, F. E., 184.Jenkins, G. L., 281.Jennings, A. P. H., 410.Jennings, J. V., 414, 445.Jennings, K. F., 323.Jenny, E. F., 212.Jensen, F. R., 66, 169,175, 194, 196, 227, 228,247.476.184.Jensen, L. H., 283, 471.Jensen, M. B., 183.Jensen, W. N., 209.Jepsen, D., 24.Jerbnimo, M. A. S., 409.Jesson, J. P., 36.Jewell, D. J., 38.Jezowsl: a-Trzebiatowska,Jha, S. S., 56.Jicha, D. C., 131.Jochims, J. C., 342.Johanneser, N. H., 48.Johansen, P. G., 321.John, E. V. O., 282, 294.B., 128.John, K., 97.Johnsen, U., 324.Johnson, A. W., 258, 271,Johnson, B. F. G., 131.Johnson, C. A., 432.Johnson, C. E., 100.Johnson, C.S., 59, 78.Johnson, D. E., 410.Johnson, E. A., 163.Johnson, G. D., 412.Johnson, L. F., 193, 277,Johnson, M. D., 179.Johnson, R., 409.Johnson, R. N., 215.Johnson, W. C., 413.Johnson, W. S., 194, 247,Johnston, C. B., 441.Johnston, I?. A., 94.Johnston, H. J., 48.Johnston, M. J., 352.Jokl, V., 408.JollPs, J., 321.Jollhs, P., 321.Jolly, W. L., 91.Jommi, G., 240.Jon&, J., 180.Jones, D., 69, 114, 115.Jones, D. N., 202, 324.Jones, E. A., 105.Jones, E. D., 429.Jones, E. R. H., 193, 210,Jones, H. C., 422, 441.Jones, I. L., 422, 431.Jones, J. K. N., 335. 336,338, 342, 352.Jones, J. L., 413.Jones, J. M., 181.Jones, L. H., 106, 135.Jones, L. L., 188.Jones, M. H., 162.Jones, M. M., 104, 105.Jones, N., 215.Jones, R.A., 41, 271, 435.Jones, R. A. Y., 75, 182,Jones, R. T., 317.Jones, T. P., 106.Jones, W. F., 401, 402.Jones, W. J., 42.Jordan, D. O., 260.Jordan, J., 452.Jorgenson, M. J . , 182.Joschek, H.-I., 235.Josefsson, L., 302.Joseph, B. W., 433.Joseph, K. T., 374.Joseph, T. C., 253.Josephson, R., 163.Josey, A. D., 61, 69.Josien, M. L., 36, 37, 38,Joska, J., 321, 323, 335.284.287, 289.296, 324, 325.259, 323.261.40, 42INDEX OF AUTHORS’ NAMES 497Jolit, K., 315.Joyner, R. D., 91.Joyner, T. B., 106.Juenge, E. C., 208.Jiinger, H., 263.Juhasz, G., 333.Julg, A., 145.Julia, M., 217.Juliard, A., 419.Juliard, A. L., 445.Jung, A., 389.Jung, H., 101.Just, G., 327.Juvinall, G. L., 84.Juza, R., 125.Kabasakalian, P., 209, 326,Kaczmarczyk, A., 90.Kaden, T., 107.Kader, N.A., 473.Kaeding, W. W., 206.Kaesz, H. D., 62, 92,93, 95,Kaganove, A,, 177.Kahn, B., 448.Kahn, L. D., 368.Kaiser, E. T., 170.Kaiser, F., 332.Kaiser, R., 29.Kakabadse, G., 417, 430.Kakisawa, H., 257.Kalidas, C., 153.Kalinowska, Z., 424.Kalvoda, J., 68, 327, 330.Kamber, B., 330.Kamenar, B., 93, 469.Kamikawa, T., 260.Kamiya, T., 333.Kamlet, M. J., 277.Kan, R. O., 279.Kanaoka, Y., 278.Kandel, S. I., 285.Kaneko, M., 298.Kanner, L. J., 413.Kapil, R. S., 287.Kaplan, F., 59.Kaplan, H., 139.Kaplan, N. O., 385.Kaplan, R. P., 210.Kappeler, H., 305, 307, 313,Karabatsos, G. S., 62, 76.Karle, J. L., 454.Karmen, A., 218, 364.Karo, A.M., 25, 139, 142.Karol, F. J., 112.Karplus, M., 58, 149, 150,Karpov, T. P., 168.Karr, C., jun., 400.Karrer, P., 217, 292, 293,Kartha, G., 375, 454, 479.Karyagine, A. A., 130.328.108, 117, 119, 236.316, 317.151.294, 478.Kasiura, K., 436.Kaska, W., 208.Kasturi, T. R., 200.Kataoka, H., 286, 297.Katayama, M., 151, 152.Katekar, G. F., 283.Kato, H., 147, 148.Kato, Y., 49, 151, 472.Katritzky, A. R., 41, 75,158, 182, 261, 268, 271,281.Katsoyannis, P. G., 306.Kaltenbronn, J. S., 283.Katz, J. J., 98, 122, 177,Katzen, H. M., 349.Kauffman, D. L., 320.Kauffmann, T., 279.Kaufmann, E., 208.Kauzmann, W., 23, 189,Kavanagh, F., 389.Kawasaki, T., 390.Kawazoe, Y., 293.Kay, I. T., 284.Kay, M. J., 457.Kayama, K., 138, 141.Kaye, W.I., 435.Kazanskii, B. A., 263.Kaziro, Y., 394.Kealy, T. J., 208, 215.Keane, F. M., 94.Keating, J., 179.Keck, J. C., 51.Keefer, R. M., 101, 163.Keenan, T. K., 121, 122.Keggi, J. J., 277, 312.Keidel, F. A., 400.Keil, B., 304.Keil, J. G., 265.Keil, K. D., 336.Kelkar, G. R., 251.Keller, H., 80.Keller, J., 330.Kelley, M. J., 425.Kelley, M. T., 422, 441.Kelly, C. A., 239.Kelly, R. B., 301.Kelly, R. G., 430.Kelly, R. J., 264.Kemmitt, R. D. W., 100.Kemp, A. L. W., 211.Kemp, D. M., 447.Kempter, C. P., 128, 462.Kemula., W., 446.Kende, A. S., 237.Kendrew, J. C., 317.Kennard, C. H. L., 134,Kennedy, J., 218.Kenner, G. W., 68, 284,Kenney, M. E., 91.Kent, P. J. C., 453.Kenten, R. H., 372, 373.Kern, C.W., 63.284.305.471.300, 301.Kern, W., 410.Kerr, J. A., 165.Kessel, I., 362.Kessler, A., 37 1.Kessler, J. E., 451.Kestenbaum, I. L., 346.Ketelaar, J. A. A., 44.Ketley, A. D., 163.Kettle, S. F. A., 69, 110.Kevorkian, V., 46.Khadeev, V. A., 421.Khairallah, P. A., 314.Khaleeluddin, K., 185.Khalifa, H., 425, 436.Kharasch, N., 210.Kheiker, D. M., 454.Khitrova, V. I., 127.Khodadad, P., 122.Khoda.shova, T. S., 111,Khorana, H. G., 261, 280.Khristulas, F. S., 333.Khundkar, M. H., 414.Khvatkina, A. N., 472.Kibitscheck, M. J., 192.Kidd, D. A. A., 210.Kiefer, J. H., 46.Kielar, E. A., 294.Kienast, G., 134.Kienitz, H., 430.Kies, H. L., 424.Kiessling, K. H., 394, 395.Kikkawa, I., 331.Kilday, B.A., 435.Killian, P. J., 348.Killick, R. A., 447.Kilner, M., 109.Kilpatrick, G. E., 251.Kilpatrick, M. L., 98, 158.Kipping, P. J., 410.Kim, J.-Y., 108, 168, 169.Kimball, A. P., 279.Kimbrough, R. D., 315.Kimura, K., 258.Kindler, H., 216.Kindler, K., 203.Kinel, F. A., 299.Kinell, P.-O., 64, 346.King, D. M., 412.King, F. E., 259, 282.King, G. W., 139.King, H. G. C., 237.King, J. P., 229.King, N. J., 350.King, R. B., 69, 111, 112,113, 114, 117, 118, 119,236, 237.King, R. W., 184, 186,241.King, T. J., 258.King, W. H., jun., 435.Kingsbury, C. A., 170.Kingsley, G. R., 437.Kingston, A. E., 26.Kingston, D., 94.Kinoshita, T., 15.468498 INDEX OF AUTHORS’ NAMESKirby, G. W., 237, 285.Kirby, R., 412.Kiriyama, R., 130.Kirk, D.N., 324.Kirkwood, J. G., 35.Kirmse, W., 178, 238.Kirschner, S., 107.Kirshenbaum, A. D., 99.Kis, J., 423.Kiselev, A. V., 45.Kiser, R. W., 412.Kishida, Y., 259.Kishita, M., 133.Kiss, S. A., 426.Kistiakowsky, G. B., 34, 47,49, 51, 52.Kita, D. A., 334.Kitahara, Y., 235.Kitano, H., 66.Kitao, T., 272.Kitaoka, Y., 272.Kittel, C., 458.Kittleman, E. T., 105.Kivelson, D., 59.Kjaer, A., 300, 301.Kliining, U., 125.Klahre, G., 204.Klanberg, F., 81, 86.Klass, D. L., 209.Klassen, N. V., 163.Klauser, H. E., 45.Kleemann, M., 240.Kleesaat, R., 89.Klein, H. P., 155, 366.Klein, J. J., 46.Klein, R., 81.Kleinberg, J., 130, 236.Kleine, K.-M., 214.Kleinschmidt, R. F., 211.Klemm, W., 80, 127, 134,Klenk, E., 219.Klesper, E., 79.Klieger, E., 310.Klimov, V. V., 438.Klimova, V.A,, 429.Klinck, R. E., 248.Klingsberg, E., 270.Klink, J. R., 159.Klipp, R. W., 437.Kluiber, R. W., 80.Klumpp, E., 109.Klyachko, Yu. A., 422.Klfgin, A. E., 416.Klyne, W., 186, 188, 256,Kneser, H. O., 30.Knevel, A. M., 281.Knight C. A., 319.Knight, H. T., 49, 52.Knipmeyer, H. E., 197.Kniiek, M., 399.Knotzel, H., 29.Knotzel, L., 29.Knopf, P. M., 467.Kliimbt, H.-D., 300.469.322.Knoth, W. H., 82.Knowles, G., 441.Knowles, J. R., 158, 162,Knowles, R. B., 293.Knox, G. R., 117, 225,Knox, J. H., 178.Knox, K., 456, 468.Knox, L. H., 179.Knudsen, A., 300.Kobata, A., 390.Kobayashi, A., 283.Kobayashi, H., 146.Koch, A. C., 314.Koch, H., 243, 246.Kochanny, G.L., jun.,Kochetkov, N. K., 341,Kochi, J. K., 119, 202.Kodama, G., 81.Korbl, J., 415.Kofier, M., 217.Koga, N., 379.Kohlmuller, R., 124.Kohlschutter, H. W., 81,Kohnstam, G., 177.Koide, T., 472.Koine, A., 343.Kokalis, 8. G., 97.Kokko, J. P., 68.Kokorev, V. V., 121.Kokorudz, M., 167.Kokot, E., 133, 468.Kokowsky, N., 307.Kolbin, N. I., 128.Kolditz, L., 98, 99, 124,Kolesnikov, D. G., 332.Kolker, P. L., 68. ,Koll, M., 292.Kolloff, R. H., 407.Kollonitsch, J., 86, 198,Kolos, W., 15.Kolski, T. L., 80.Kolthoff, I. M., 420, 422.Kolyada, N. S., 416.Komatsu, K., 341.Komatsu, T., 338.XComissarenko, N. F., 332.Konigsberg, W., 317.Konkol, W., 305.Kononenko, 0. K., 346.Konovalenko, 0.S., 101.Konrad-Jakovac, Z., 408.Konzett, H., 314.Koopmans, T. A., 14.Kooyman, E. C., 159.Kopecky, K. R., 178.Kopoldova, K., 304.Kopple, I(. D., 125, 312.Kornblum, N., 207.Kornegay, W., 48.164.237.125.343.86.125.266.Korte, F., 390.Koskie, W. S., 81.Kosower, K. M., 234.Kosta, L., 413.Koster, R., 82, 198, 237.Kostka, V., 304.Kotake, M., 333.Kotani, M., 138, 141.Kotelko, A., 266.Kounina, 0. V., 367, 369.Koutecky, J., 147,158,266.Kouwenhoven, H. W., 112.Kovach, E., 189.Kovacic, P., 230.KOV~V, J., 248.Kovshunov, B. G., 121.Kowalczyk, J., 408.Kowalewski, V. J., 73.Kowalsky, A., 68, 302.Kowitz, F., 212.Koyama, K., 441, 445.Kozikowski, J., 118.Kozima, K., 41, 196.Kraak, A., 212.Kr&Emar, J., 435.Kraihanzel, C.S., 41.Kramolowsky, R . , 1 1 1.Krampitz, L.-O., 395.Kranz, Z. H., 220.Krapcho, A. P., 179, 238.Krasch, H., 251.Krasnitskaya, A. L., 402.Kratochvil, B., 425.Kratochvil, K., 415.Kratochvil, M., 416.Kratochvil, V., 402.Kraul, R., 403.Kraus, K. W., 205.Krause, R. A., 131.Krauss, H.-L., 101, 126.Krauss, M., 27, 139, 142.Kraut, J., 472.Kreevoy, M. M., 75, 169.Kreil, G., 317.Kreimer, S. E., 405.Krell, M. W., 36.Kresge, A. J., 153,154, 155.Krespan, C. G., 213, 223.Kriegsmann, H., 91.Krill, H., 90.Krimse, W., 179.Krishnamurty, R. V., 103.Krishnan, V. R., 424.Krishna-Prasad, Y. S. R.,Krohnke, F., 271.Kromhout, R. A., 76.Kroner, T. D., 376.Kruck, T., 109.Kriickeberg, F., 56.Kriierke, U., 116, 223, 232.KrupiEka, J., 305.Kruse, C.W., 211.Kubba, V. P., 167.KubinoviL, M., 437.Kublik, Z., 446.302INDEX OF AUTHORS’ NAMES 499Kubo, M., 66, 133.Kubota, T., 256,260.Kuboyama, A., 145.Kuchmistaya, G. I., 434.Kuck, J. A., 429.Kuczynski, H., 249.Kiibler, H., 378.Kuchlewind, W. E., 231.Kiihn, J., 377.Kiihn, K., 374, 375, 377.Kuehne, M. E., 255.Kuhn, H., 143.Kuhn, R., 172, 231, 339,Kuhn, S. J., 161, 230.Kuivila, H. G., 92, 154,Kulkarni, A. B., 260.Kulkarni, G. H., 251.Kumamato, J., 470.Kumazawa, Z., 257.Kummer, D., 88.Kumov, V. I., 401.Kunchur, N. R., 468.Kunde, J., 220.Kune, K., 76.Kuntz, I. D., 62.Kupchan, S. M., 180.Kupfer, D., 327.Kupinskaya, G. V., 163.Kurek, L.I., 388.Kurita, Y., 63, 152.Kuriyama, M., 301.Kurono, M., 257.Kursanov, D. N., 231.Kurtz, A. N., 309.Kurtz, E. B., 365.Kurzer, F., 270.Kusch, K., 334.KUSSY, M. E., 404, 405,Kusumoto, H., 70.Kuta, E. J., 444.Kutney, J. P., 287.Kuwana, T., 117.Kuwata, K., 45.Kuzel, P., 112, 113.Kvashina, F. F., 421.Kwart, H., 279.342, 343.160.448.Lablache-Combier, A., 323.Lbbler, L., 321.Labre, J., 420.Labut’ev, Yu. D., 422.Lacam, A., 322.Lacey, R,. N., 221.Lachance, J. P., 354.La Combe, E. M., 205.Lacy, J., 400, 410.Lada, Z., 415.Ladd, M. F. C., 427.Ladik, J., 25.Lafaix, A., 42.Lagowski, J. M., 158, 271.Lai, T. T., 441.Laird, W., 258.Laitinen, H. A., 420, 423,Lalancette, E. A., 240.La Lou, C., 38.Lamb, J., 28.Lambert, J.D., 31.Lambert, J. L., 428.Lambert, R., 342.Lambert, R. F., 109.Lamberton, J. A., 220.Lampe, F. W., 148.Lande, S., 315, 316.Landgrebe, J. A., 169.Landis, A. L., 135.Landolt, R., 316.Landor, S. R., 178,193,214,Landowne, R. A., 219, 410.Landrum, B. F., 225.Landucci, J. M., 372.Lane, E. S., 417.Lanford, C. E., 394.Lanfredi, A. M., 470.Lang, K., 81.Lang, R. P., 102.Langdon, R. G., 353.Langdon, W. K., 167.Langella, M. R., 268.Langemann, A., 217.Langer, H., 93.Langer, L. J., 321.Langford, C.-H., 154.Langham, W. H., 383.Lanigan, P. G., 124.Lanni, F., 304.Lansbury, P. T., 200, 203.Lantz, C. D., 322.Lam, P., 311.Lanzi, G., 78.La Placa, S., 462.Lappert, M. F., 75, 83, 84,Lappin, G.R., 272.Lardy, H. A., 353.Large, D. G., 313.Larrson, K. E., 460, 477.Larsen, P. O., 300, 301.Larson, R. C., 441.Lascombe, J., 36, 37, 38,Laszlovsky, J., 414.Latz, H. W., 433.Lau, C. L., 451.Lau, H. H., 186.Laubengayer, A. W., 84,Lauder, I., 184.Lauer, C., 265.Lauryssens, J., 353.Lauterbur, P. C., 62,E5, 67,Laver, W. G., 302.Laviron, E., 445.Law, H. D., 315.Lawesson, S. O., 202, 266.427.244.90, 93.40, 41, 42.86.93, 158.Lawrence, R. V., 256.Lawrie, T. D. V., 219.Lawson, J. E., 203.Lawson, W. B., 303.Lawton, R. G., 174.Lawyer, C. B., 216.Layton, E. M., 143.Lazdins, D., 159.Leach, A. A., 367.Leaf, A. C., 448.Lease, M. F., 95, 201.Leaver, D., 270.Lebeau, M. C., 302.Lebedev, V. G., 91.Lebedeva, A.I., 430,432.Leblanc, E., 119.Lecerf, A., 123.Leciejewicz, J., 462.le Count, D. J., 289.L’lhuyer, P., 230.Leder, I. G., 390, 391.Lederer, E., 218, 219, 256,257, 301, 321.Le Dizet, P., 336.Lednicer, D., 189.Ledsham, K., 22.Ledwith, A., 176, 178, 221.Lee, J., 83.Lee, J. B., 341.Lee, T. H., 315, 316.Lee, W. E., 209.Lee, W. H., 427.Lee, Y. K., 108, 168.Leebrick, J. R., 205.Leermakers, P. A., 178.Leete, E., 277, 285, 286.Lefebvre, R., 25, 142, 152.Lefebvre-Brion, H., 26, 27.Le FGvre, R. J. W., 36.Leffek, K. T., 155.Lefort, M., 102.Legge, N., 43.Legler, G., 376.Legrand, M., 189, 322, 323.Legvold, S., 31, 32, 33.le Hir, A., 290, 292.Lehmann, H.-A., 100.Lehmann, J., 337.Lehmann, R., 100.Lehmann, W.J., 85.Lehn, J.-M., 323.Lehn, W. L., 272.Lehninger, A. L., 353.Leibbrand, K. A., 264.Leibowitz, J., 259, 336, 341.Leibsohn, R., 406.Leicknam, J. P., 37, 40,Leifer, E., 383.Leigh, G. J., 90.Leigh, W. R. D., 347.Leikhim, E., 320.Leimgruber, W., 299.Lein, J., 388.Lein, P. S., 388.Legoux, Y., 121.42500 INDEX OF AUTHORS’ NAMESLeisten, J. A., 177, 182.Leithe, W., 433.Leja, J., 41,Leliaert, G., 449.Lemal, D. M.. 246.Le Men, J., 292.Lemieux, R. U., 59, 68, 275.Lemons, J. F., 76.Lenaers, R., 269.Lenci, M. T., 314.Lenhert, P. G., 480.Lennard-Jones, J., 140,141,Lennox, E. S., 386, 387.Lents, C., 418.Le Nye, G., 174.Lenz, R. W., 64.Leonard, G. W., 444.Leonard, J. A., 209.Leonard, N. J., 261.Leonard, M.A., 432.Leonov, V. N., 332.Lerch, A., 221.Lergier, W., 311, 313.Lerner, A. B., 315, 316.Lerner, P., 386. .Lester, G., 388.Lets, J. R., 211, 222.Lets, M. F., 211, 222.Leuthardt, F., 280, 394.Levenberg, B., 301.Levenson, S. M., 371.Levin, Y., 317.Levina, R. Ya., 242, 274.Levine, L., 320.Levisalles, J., 258, 323.Levitus, R., 128.Levy, D. A., 69.Levy, E. J., 410, 450.Levy, H. A., 455, 457.Levy, J. F., 176.Levy, M., 373, 374.Levy, N., 285.Lewin, R., 82, 461.Lewin, S., 399.Lewinson, J., 445.Lewis, A., 59.Lewis, D. G., 272.Lewis, D. T., 422.Lewis, E. S., 155, 185.Lewis, G. P., 313.Lewis, I. C., 164.Lewis, J., 41, 105, 111, 112,120, 123, 126,466,468.Lewis, J. W., 80.Lewis, M. S., 369, 378.Lewis, P.A., 441.Lewis, T. R., 287.Leysath, G., 313.Lhermite, Y., 75.Li, C. H., 315, 316.Li, N. C., 177.Libergott, E., 403.Liberman, A. L., 263.Lichtenberger, J., 241.Lichtin, N. N., 155.148.Liddle, A. M., 337, 349.Lieb, H., 429.Liebe, W., 127, 469.Lieber, E., 94.Liebig, J., 434.Liebster, J., 304.Likhosherstov, L. M., 341.Limon, D. C., 197.Lin, C. C., 26, 153.Lin, S. C., 48.Lind, M., 128.Lindahl, C. B., 121.Lindberg, B., 337, 338, 343.Lindeman, L. P., 450.Linden, P., 348.Linderberg, J., 21.Lindner, E., 109, 119.Lindner, E.-B., 316.Lindqvist, I., 463.Lindsey, R. V., 100, 216,Linevsky, M. J., 38.Lingafelter, E. C., 126, 132,Lingane, J. J., 427.Linnell, R. H., 274.Linnett, J. W., 53, 79, 103,Linzer, B., 378, 380, 381,Lioret, C., 301.Lippert, E.L., 134, 465,Lippincott, E. R., 116, 438.Lipscomb, W. N., 63, 82,114, 454, 461, 463, 464,472, 477.Lipsky, S. R., 410.Lipson, H., 453.Liptay, G., 452.Lipton, M. A., 394.Lisk, D. J., 429.List, P. H., 300.Lister, M. W., 107.Liteanu, C., 424.Litovitz, T. A., 28, 30.Little, L. H., 36, 38, 41, 45.Liu, C. F., 133.Liu, C. H., 133.Liu, T.-Y., 316.Livingstone, J. G., 83.Li-Yuan Hsii, 417.Llanos, A., 237.Llewellyn, D. R., 183.Llewellyn, J. A., 155.Lloyd, A. G., 351.Lloyd, H. A., 286, 294.Lloyd, N. A., 441.Lloyd, P. J., 405.Lo, T.-B., 316.Loader, B. E., 46.Lobachev, A. N., 455.Lobanov, N. I., 101.Locchi, S., 476.Lock, C. J. L., 127.Locke, J. M., 203263.454, 469, 471, 474.142, 146.382.472.Lockhart, J., 231, 239.Lockyer, T.N., 134.Loder, E. R., 433.Loder, J. D., 193.Lodge, J. E., 211, 224.Loeffler, P., 208.Lofgren, P., 102, 126.Lofgren, T., 454.Loembergen, N., 78.Lowdin, P.-O., 8, 18, 19,20, 26, 28, 138, 140, 141,142.Loewe, L., 153.Logan, J. S., 198.Logan, M. A., 375, 376.Logan, N., 131.Logan, T. J., 199, 214.Lohmar, R. L., 218.Lohmeyer, S., 80.Lohofer, F., 110.Lohr, L. J., 426.Lombard, R., 256.Lomekhov, A. S., 405.Long, A. G., 324.Long, F. A., 153, 154, 156,Long, L. H., 82.Long, R. A. J., 231.Long, R. W., 361.Longo, F. H., 221.Longo, J., 127.Longstaff, J. V. L., 25.Longuet-Higgins, H. C., 28,103, 142, 143, 144, 149.Lonsdale, K., 455, 459.Loriaux, H., 153.Lorica, A.S., 404.Lorquet, J.-C., 27.Losev, S. A., 46, 52.Losin, E. T., 245.Losse, G., 305, 307.Love, C. W., 68.Love, D. L., 441.Loveland, J. W., 444.Lovelock, J. E., 410.Loveridge, B. A., 447.Lovtsova, A. N., 178.Low, M., 247.Lowe, G., 214.Lown, J. W., 68.Lowry, B. R., 245.Lowry, R. E., 224.Lowther, D. A., 371.Loyd, R. J., 410.Lozinskaya, V. S., 402.Lu, D. C., 446.Lucchesi, P. J., 45.Ludsteck, D., 262.Ludwick, J. D., 449.Ludwig, P., 115.Lubke, K., 310.Luttringhaus, A., 275.Luis, P., 401.Lukasik, S. J., 29.Lukaszewski, G. M., 452.Lukaszewski, H., 206.170INDEX OF AUTHORS' NAMES 501Lukin, M., 373.Lukina, V. I., 431.Lukton, A., 266.Lumpkin, H. E., 450.Lumry, R., 68, 305.Lund, E., 302.Lund, M. A., 433.Lunde, K., 196, 246.Luskina, B.M., 432.Lustig, E., 74.Lutz, E. F., 211,223.Lutz, R. P., 59.Lux, H., 125.Lux, R., 418.Luxmoore, A. R., 464.Luzzati, V., 476.Lyashenko, V. D., 184.Lyerly, L. A., 404.Lygin, V. I., 45.Lykos, P. G., 139, 140, 143,Lynch, G. R., 45.Lynden-Bell, R. M., 62.Lynen, F., 353, 362, 364.Lynton, H., 466.Lyon, R. K., 34.Lyubimov, Yu A., 46.149.Ma, S. Y., 284.Ma, T. S., 403, 426.Maak, I., 469.Maas, L. W., 203.Mabbs, F. E., 105.McArthur, R. E., 231.McCapra, F., 281.McCarthy;, P. J., 106.McCarty, M., 39.McCasland, G. E., 193.Maccioni, A., 192.McClellan, W. R., 114, 119,McClelland, B. J., 146.McCloskey, A. L., 83, 85.McCloskey, J. A., 421.Maccoll, A., 185.Mcconnell, H.M., 150, 151,236, 268.152.262, 278, 478.32, 33.McCorkindale, N. J., 218,McCoubrey, J. C., 28, 31,McCoy, L., 238.McCrea, P. A., 219.McCrindle, R., 259.McCusker, P. A., 200.MeDaniel, J. C., 175.MacDiarmid, A. G., 87, 88,Macdonald, A. M. G., 398,McDonald, E. J., 337.McDonald, J. E., 442.MacDonald, S. G. G., 474.McDonald, T. R. R., 456.99.429, 431.McDowell, J. W., 200.McElroy, W. D., 281, 383.McEwen, K. L., 146.McEwen, W. E., 236.McFadden, G. H., 341.McFarland, J. W., 197.McFarlane, W., 113.McGarr, J. J., 376.McGavins, 375.McGeachin, H. McD., 98,MacGillavry, C. H., 474.McGinn, C. J., 191.McGlotten, J., 328.McGrath, J. W., 76.McGrath, W. D., 433.McGreer, D. E., 60.MacGregor, P., 237.MeGregor, W.H., 306.McGuire, F. J., 209, 252.Machacek, M., 17.Machata, G., 398.Machleidt, H., 334.Macintosh, E., 443.McIntyre, J. E., 202.McIver, E. J., 179.Mack, W., 270.McKay, J. E., 348.MacKay, K., 98.McKee, K. H., 435.MacKellar, F., 75.McKenzie, E. D., 134.Mackenzie, J. D., 78.McKenzie, S., 188.McKeon, J. E., 277, 312.McKibbins, S. W., 407.Mackie, I. M., 350.Mackie, R. K., 84.McKinnell, J. P., 351.Mackintosh, W. D., 447.Mackor, E. L., 65, 66, 75,McKusick, B. C., 213, 223.McLachlan, A., 65, 151.McLachlan, A. D., 58, 152.McLain, L. W., jun., 354.McLean, A. D., 24, 27, 139.Maclean, C., 65, 66, 75.MacLean, J. W., 223.MeMorris, T. C., 327.McNabb, W. M., 442.McKamee, P. I., 343.McNary, J.E., 300.McNees, R. S., 245.McNinch, J. A., 208.McNutt, R. C., 443.McNutt,, W. S., 280.McOmie, J. F. W., 227, 228,McPhail, A. T., 292, 293,McShan, W. H., 365.McWeeny, R., 27, 138, 139,140, 142, 145, 150, 153.McWhan, D. B., 460.MeWilliam, I. G., 409.462.443.233.478.Madigosky, W. M., 30.Maeck, W. J., 404, 405,448, 449.Marki, F., 278.Markl, G., 203, 204.Maetz, J., 314.Maezono, N., 333.Magarajan, K., 67.Magat, M., 35.Magee, R. J., 433.Mahajan, J. R., 209, 252.Maher, J. P., 57.Mahler, H. R., 358.Mahler, W., 96.Maier, E., 100.Maier, G., 233.Maier, W., 67.Mainwald, J., 49.Mair, G. A., 132, 465, 466.Mairinger, F., 96, 123.Maitlis, P. M., 167, 240.Majer, R. J., 450.Majumdar, M. K., 84.Majumdar, R., 425.Majumdar, Santosh K., 312,Mak, T.C.-W., 182.Makarov, N. V., 326.Maki, A., 44.Malatesta, L., 110, 120,232.Malik, W. U., 426.Malikov&, J., 321.Malinowski, E. R., 62.Malinowski, J., 434.Malkin, T., 219.Malli, G. L., 139.Malling, G. F., 405.Malm, J. G., 127, 128.Malmberg, E. W., 209.Malmstadt, H. V., 426.Malyanov, V. A., 168.Mamentov, G., 419.Manahan, J., 374.Manaresi, R. R., 407.Manasevit, H. M., 83.Manastyrskyj, S. A., 118.Manatt, S. L., 70.Mandell, L., 64, 68, 251,Mandels, M., 345.Mander, L. N., 256.Mandl, I., 374.Mangoni, L., 256.Mangum, B. W., 153.Manley, R. St. J., 347.Mann, F. G., 225.Mann, T., 98.Mannella, G., 53.Manners, D. J., 349, 351.Manning, D. L., 405, 418,Mannougek, O., 184.Mano, Y., 394.Manohar, H., 292.Manohin, B., 430.Manson, A.J., 323.405.286.428502 INDEX OF AUTHORS’ NAMESManson, P. R., 46.Mantell, G. J., 273.Manuel, T. A., 113, 114,Mapper, D., 446.March, N. H., 456.Marcoux, J., 31.Marczenko, Z., 436.Marezio, M., 121, 470.Margoliash, E., 317.Margrave, J. L., 79, 194,Margulis, T. N., 87, 463.Mariani, L., 206, 262.Marica, E., 233.Marinder, B.-O., 125.Marini-Bettslo, G. B., 287.Marion, L., 286, 298, 478.Mark, T. C. W., 234.Mark, V., 208, 234.Markgraf, J. H., 178.Markina, V. Y., 81.Markley, F. X., 252.Marko, A. M., 367.Mark6 L., 109.Markov, B. F., 123.Markowitz, M. M., 452.Marks, G. S., 321.Markunas, P. C., 418, 426.Marquard, K., 307.Marquardt, H.-W., 334.Marra, J.V., 200.Marsh, D. W., 104.Marsh, J. F., 82.Marsh, R. E., 457, 479.Marsh, S. F., 405, 449.Marshall, H., 327.Marshall, J. A., 255.Marshall, J. C., 101.Marshall, R. D., 321.Marshall, R. R., 450.Marshall, T. W., 70.Marshall, W., 22, 152.Marshall, W. L., 169.Marshall-Jones, P., 188.Marszak, I., 211.Martel, J . , 324.Martell, A. E., 106, 425.Martell, C., 110, 465.Martin, D. B., 218, 364.Martin, F., 431.Martin, G., 62.Martin, G. R., 378.Martin, H. V., 322.Martin, J., 124.Martin, J. C., 439.Martin, J. G., 186.Martin, M., 74, 75.Martin, R. J., 258.Martin, R. L., 134.Martin, S. B., 410.Martin, Ifi. W., 104.Martino di Castrozza, S.,Martin-Smith, M., 260.Martire, D. E., 409.118.247.432.Marton, L., 460.Marugid, K., 190.Masaguer, J.R., 96.Masamune, S., 255, 257.Maslen, E. N., 478.Maslennikova, A. G., 36,Masler, L., 332.Mason, R., 132, 466, 475.Mason, S. F., 145.Masschelein, W., 41.Masse, J.-L., 26.Massey, A. G., 85, 101.Mataga, N., 144, 145.Mataga, S., 144, 146.Mateescd, G., 233, 274.Mather, W. B., 424.Mathes, K. J., 365.Matheson, A. J., 31.Mathews, D. L., 30.Mathews, F. S., 477.Mathews, T., 153.Mathewson, J. H., 284.Mathias, A. P., 320.Mathieson, A. McL., 478.Mathieu, J., 322, 333.Mathieu, M. V., 44.Mathur, S. K., 415.Matkovi6, B., 466.Matkovich, V. I., 461.Matrka, M., 444.Matsen, F. A,, 17, 22, 25,Matsuda, K., 345.Matsui, H., 181.Matsui, M., 283.Matsumae, T., 442.Matsumiya, H., 68.Matsumoto, T., 260, 298.Matsuoka, S., 66.Matsushita, S., 45.Matsuura, T., 260.Matsuyama, G., 422.Mattack, G.M., 448.Matteson, D. S., 264.Matthews, D. L., 48, 52.Matthies, D., 203.Matveeva, N. G., 103.Mavel, G., 62, 75.Maxwell, J. L., 163, 183.May, I., 124.May, W. R., 472.Mayer, A., 369.Mayer, H., 269, 308.Mayers, D. F., 13.Mayot, M., 25.Mays, M. J., 90.Mazourov, V. I., 367, 369.Mazur, Y., 255, 328.Mazzanti, G., 221.Mazzucato, V., 176.Meadows, J. W. T., 448.Meakins, G. D., 41.Mechanic, G. L., 374.Mechkovskii, S. A., 409.Mechoulam, R., 259, 299.41.26, 456.Meckstroth, W., 347.Meechan, E. J., 420, 437.Meek, D. W., 96.Mehalchick, E. J., 433.Mehrotra, R. C., 123.Mehta, M. M., 442.Meiboom, S., 76.Meienhofer, J., 314,315,316.Meier, W., 332.Meilman, E., 373, 374.Meinwald, Y., 176, 190,337.Meisel, H., 267.Meister, W., 83, 410.Meites, L., 441.Melamed, G., 203.Melander, L., 160.Meldrum, A.N., 273.Melera, A., 293, 299.Mellor, A. S., 190.Mellor, J. R., 131.Meloun, B., 304.Melpolder, F. W., 410.Mempel, D., 347.Menard, Id., 270.Mengler, H., 265.Menis, O., 405, 418, 423,Mercer, G. A., 349.Merrill, C. I., 100.Merritt, R. F., 244.Mertz, C., 171.Meshreki, M. H., 341.Metcalfe, L. D., 407.Metlesics, W., 223.Mhtras, J.-C., 474.Metz, C. F., 452.Metzger, J. T. H., 292.Metzler, D. E., 395.Meuthen, B., 467:Meyer, C., 429.Meyer, K., 332.Meyer, M:W., 158.Meyer, N. J., 32, 50.Meyer, R. B., 207.Meyerson, S., 229, 231.Meyer zu Reckendorf, W.,Meystre, C., 331, 330.Mez, H.-C., 126, 469.Mian, A.J., 351.Michael, K. W., 91, 175.Michaelis, R. E., 435.Michaels, S., 374.Michal, J., 402.Michalski, E., 422.Micheel, F., 267, 347.Micheli, R. A., 322.Michelson, A. M., 261, 275,Mihailovi6, M. L., 330.Mihalyi, E., 376.Mii, S., 353, 358.Mijovid, M. P. V., 300.Mikeg, O., 304, 320.Mikhailov, B. M., 83.Mikhailov, V. A., 121.428.344.280INDEX O F AUTHORS’ NAMES 503Mikhaleva, Z. A., 416.Mikheev, E. P., 108.Mikheeva, V. I., 81.Miki, T., 332.Mikolajczak, K. L., 218.Mikulaschek, G., 100.Milas, N. A., 246.Mil’chev, V. A., 422.Miles, T. D., 407.Milhailovid, M. L., 330.Millard, M., 90.Milledge, J., 459.Miller, A., 282.Miller, C.S., 395.Miller, E. S., 355.Miller, G. L., 347.Miller, H. C., 82.Miller, J., 164, 171.Miller, J. G., 181.Miller, J. R., 132.Miller, R., 216.Miller, R. E., 165.Miller, W. T., jun., 213.Milligan, D. E., 43, 179.Millikan, R. C., 43, 78.Millionova, M. I., 375.Mills, H. H., 471.Mills, I. M., 27, 41.Mills, J. S., 209, 329.Mills, 0. S., 113, 464, 465.Mills, R. L., 460.Milne, G. W. A., 256.Milner, G. W. C., 421, 444,445, 449.Milward, R. C., 31, 33.Minato, H., 252.Mineo, J., 125.Miramon, A., 365.Mironov, A., 252.Mironov, V. F., 87.Mironova, A. S., 107.Mishchenko, K. P., 426.Mishra, H. C., 102.Mislow, K., 188, 191, 193.Mitchell, A., 209, 326.Mitchell, H. K., 383, 385.Mitchell, M. J., 228.Mitchell, R.W., 78.Mitra, R. B., 251.Mitsui, T., 400, 430.Mittag, E., 270.Mitzui, T., 459.Miwa, T. K., 218.Miyagawa, I., 152.Miyake, A., 301, 342.Miyano, M., 283.Miyatake, K., 332.Miyazaki, M., 259.Miyazawa, T., 43.Mizuhara, S., 301, 395.Mizuno, Y., 138, 141, 150.Mobbs, R. H., 224.Moccia, R., 25.Mochel, W. E., 225.Mock, W. L., 95, 201.Modry, F., 126.Moller, K. E., 243.Moeller, T., 97.Moelwyn-Hughes, J. T.,101, 441.Moerikoffer, A. W., 199.Moews, P. C., 84.Moffatt, J. G., 280.Moffitt, W., 142, 153, 188,Moggridge, R. C. G., 392.Mohacsi, E., 170.Mohan Rao, V. K., 407.Mohanty, G. P., 134.Mohrbacher, R. J., 291.Molodstev, N. V., 343.Momiyama, S., 441.Money, R. K., 460.Moniz, W. B., 66.Monk, R. G., 446.Monkovid, I., 192, 221.Monnier, D., 443.Monod, J., 385.Monson, P.R., 30.Montanari, F., 192.Montgomery, E. M., 349.Montroll, E. W., 54.Moore, B., 292.Moore, D. W., 59.Moore, E. J., 423, 425.Moore, N., 26.Moore, P. T., 193.Moore, S., 320.Moore, W. R., 193,243,244.Moormeier, L. F., 205.Morachevskaya, M. D., 449.Moralee, B. E., 378.Moran, R. D., 289.Moran, R. M., jun., 209.Morand, P. F., 183.Morel, F., 314.Morgan, D. J., 131.Morgan, E., 441.Morgan, E. D., 218.Morgan, J. E., 53.Morgan, J. W., 447, 449.Morgan, J. W. W., 259,282.Morgan, K., 351.Morgan, K.’J., 41.Morgan, L. O., 78.Morgan, L. R., 179, 272,Morgan, R. S., 304.Morgan, W. T. J., 352.Mori, M., 134, 467.Mori, Y., 289.Morita, T., 147.Moritz, A.G., 41.Morman, J. F., 38, 41.Morokuma, K., 147.Morosin, B., 469.Morozov, I. S., 121, 123.Morris, A. G. C., 416.Morris, C. J., 306.Morris, D. F. C., 447.Morris, I. G., 298.Morris, J. B., 145.322.296, 329.Morris, J. R., 166, 265.Morris, L. J., 218, 219.Morrison, A., 257.Morrison, G. A., 323.Morrison, H., 203.Morrison, W. R., 219.Morriss, F. V., 207.Mortimer, P. I., 283.Moscowitz, A., 188, 189,Moser, C., 26, 139, 142, 151.Moser, W., 93.Mosettig, E., 257, 297.Mosher, H. S., 208.Mosher, W. A., 203.Moskalyk, R. E., 417.MOSS, J. A., 368, 372.Moss, J. B., 299.Moss, P., 416.Motas, M., 134.Motl, O., 253.MouEka, V., 405.Moussebois, C., 269.Mowery, D. F., jun., 337,Moye, C. J., 281.Moynehan, T. M., 209.Muckenhuber, E., 121.Mudd, B., 365.Mudd, S.H., 277.Mueller, C. R., 141.Muller, E., 262.Miiller, H., 460.Muller, H. R., 201.Muller, R., 108.Muller-Schiedmayer, G., 95.Miinich, J., 413.Muetterties, E. L., 82, 96,Muir, H. M., 367.Mukaiyama, T., 220.Mukherjee, A., 151.Mukherji, A., 63.Mukherji, Anil K., 402.Mulay, C. N., 77.Mulay, V. N.,m431.Mullen, P. W., 425.Muller, E., 242.Muller, G., 324.Muller, N., 69.Mulliken, R. S., 27, 139,142, 144, 165.Mulloy, J. A., 346.Multari, R. K., 126.Mumm, O., 268.Mumma, R. O., 68.Munday, L., 302.Muneimiya, S., 262.Muiioz R., 25.Munoz Vega, M., 258.Munro, H. N., 399.Munro, J. D., 117, 237.Munsell, M. W., 167.Muntoni, F., 403.Murai, F., 287.Murata, I., 235.322.339.114, 236504 INDEX OF AUTHORS’ NAMESMurawski, D., 262.Murdoch, G.C., 221.Murdock, C. C., 460.Murgulescu, I., 178.Murphy, J. W., 405.Murphy, R. B., 399.Murphy, W. A., 321.Murray, A. W., 333.Murray, B. B., 76.Murray, K., 343.Murray, K. E., 220.Murray, K. H., 198.Murray, R. D. H., 334.Murray, R. W., 81.Murrell, J. N., 145, 146, 149.Murt, E. M., 433.Murti, V. V. S., 315.Murto, J., 171.Musgrave, W. K. R., 102,224, 432.Musher, J. I., 58, 64.Musolf, M. C., 91, 175.Muth, K., 227.Muto, Y., 133.Naar-Colin, C., 60.Nadeau, H. G., 81.Nadler, M. R., 128, 462.Naemura, K., 190.Nagahara, S., 148.Nagai, T., 446.Nagai, Y., 151, 375.Nagakura, S., 147, 148.Nagarajan, R., 327.Nagata, C., 147, 148, 158.Nagata, W., 331.Nageotte, J., 367.Nagy, P., 112.Nagpary, J., 294.Nahabedian, K.V., 154,160.Nahringbauer, G., 463.Nahun, L. Z., 420.Nair, M. D., 288.Naito, T., 273.Nakada, H. I., 354.Nakagawa, M., 190, 276.Nakai, Y., 45.Nakajima, M., 257.Nakajima, T., 146.Nakamoto, B., lo&Nakamura, A., 232.Nakamura, S., 110.Nakamura, T., 347.Nakano, T., 256, 299.Nakashima, R., 442.Nakata, H., 273.Nakata, T., 45.Nakayama, H., 392.Nakazaki, M., 283.Namba, Y., 476.Nambara, T., 323.Namkung, M. J., 209.Niiniisi, P., 341.Napier, D: R., 227.Naqui, S. M., 75.Narasimhan, P. T., 63.Narebska, A., 437.Narita, K., 319.Nasakina, M. I., 159.Nash, C. P., 132.Nast, R., 111, 133.Nath, R. L., 176.Nathans, R., 456.Natta, G., 221.Nauta, W.T., 205.Navriitil, F., 444.Nawrath, G., 220.Naya, S., 454.Naypol, K. L., 169.Nazarova, L. A., 107.Nebergall, W., 93.Necqoiu, I., 175.Nbdelec, L., 333.Nedorost, C., 414.NedvBdov&, V., 443.Needleman, S. B., 304.Nefkens, G. H. L., 305, 308.Negoiu, D., 421.Neilson, A. H., 20.Nelson, E. C., 346.Nelson, G. B., 448.Nelson, N. A., 235.Nelson, S. M., 130.Nemeth, P. E., 286.Nenitzescu, C. D., 233, 274.Nenitzescu, C. O., 175.Nes, W. R., 297.Nesbet, R. K., 22, 26, 27,Nesmeyanov, A. N., 117,Neu, R., 403.Neuberger, A., 321, 367.Neubert, G., 380, 381.Neuenschwander, P., 406.Neuman, W. F., 378.Neumann, F., 326.Neumann, H. M., 102.Neurath, H., 320.Neuss, N., 292.Newbold, J., 68.Newman, D.G., 426.Newman, E. J., 413.Newman, G., 134.Newman, M. S., 189, 206.Newnham, R., 457.Newton, D. C., 449.Newton, G. G. F., 478.Niccolini, M., 130.Nicholas, R. D., 177.Nicholls, D., 123, 124.Nichols, H. A., 445.Nicholson, D. E., 46.Nicholson, M. M., 446.Nickon, A., 202, 209, 252.Nicolaides, E. D., 313.Niedenzu, K., 84.Niederpriim, H., 89, 90.Niederwieser, A., 304.Nielsen, B. E., 335.Nielson, H., 394.139.168.Nielson, W. D., 170.Niemann, C., 309.Niemier, J., 122.Nightingale, D. V., 221.Nikitin, E. E., 51.Niles, E. T., 243.Nimz, H., 343.Nishi, H. H., 421.Nishigai, M., 375.Nishimoto, K., 144, 145.Nishiura, P. Y., 325.Nitecki, D. E., 312.Nitta, I., 467.Noble, N. L., 378.Noda, C., 289.Noda, H., 375.Noe, F.F., 300.Noe, J. L., 403.Noth, H., 81, 83, 90, 96, 98,Nogina, 0. V., 117.Noguchi, J., 341.Noguchi, S., 335.NominB, G., 332.Nonhebel, D. C., 231.Nooi, J. R., 212.Norcross, B. E., 1-59.Nord, F. F., 237.Nordh, L., 343.Nordin, I. C., 208.Nordman, C. E., 460.Nordsieck, H. H., 466.Nordwig, A., 375, 376.Norin, T., 253.Norman, N., 475.Norman, R. 0. C., 158, 162,Normant, H., 215.Norrish, R. G. W., 29, 51.North, A. T., 375.North, R. J., 47.Northcote, D. H., 350.Norwitz, G., 413.Norymberski, J. K., 327.Nose, Y., 390.Novikova, K. F., 432.Novotnf, L., 252.Novozhilova, I. V., 432.Nowacki, W., 453, 470.Noyce, D. S., 66, 182, 194,Noyce, W. K., 186.Nozaki, H., 228, 253.Nozaki, T., 448.Nozaki, Y., 333.Nozoe, S., 325.Nozoe, T., 251.Niibel, G., 280.Nuenke, R.H., 321.Niirnberg, E., 408.Niirnberg, H. W., 440.Nunes da Costa, M. J., 409.Nursten, H. E., 237.Nussbaum, A. L., 209, 325.Nussim, M., 328.Nussin, M., 198.100.163, 164.196INDEX OF AUTHORS’ NAMES 505Nuttall, R. H., 104.Nyburg, S. C., 131, 468.Nyc, J. F., 383.Nyholm, R. S., 41,103,104,112, 120, 123, 126, 129,132, 466.Nylund, A., 461.Nyman, C. J., 441, 443.Oae, S., 272.Oakes, D., 265.Oberlin, M., 347.O’Brien, R. E., 193.O’Brien, R. J., 132.Occolowitz, J. L., 408.Ochiai, E., 298.Ochoa, S., 353.O’Colla, P. S., 346.O’Comor, J. M., 291.O’Connor, R., 400.Oda, R., 262.Oda, T., 454, 472, 476.O’Donnell, I. J., 304.O’Donnell, J. J., 346.Oediger, H., 216.Ofele, K., 109.Ofner, A., 217.Oftedahl, M.L., 342.Ogawa, I. A., 175.Ogawa, K., 130.Ogle, J. D., 375, 376.Ohloff, G., 251.Ohme, R., 261, 262.Ohno, K. A., 27, 139.Ohno, M., 192, 238, 251.Ohta, T., 289.Okada, Y., 324.Okamoto, T., 298.Okamy, A., 285.Okanishi, T., 333.Okano, A., 332.Okano, M., 262.Okawara, R., 92, 93.Okaya, Y., 91, 175.Okazaki, A., 134, 468.O’Keefe, J. G., 77.Okhi, E., 325.Okbn, K., 162.Oksne, S., 281.Okuda, M., 46.Okuda, S., 286, 297.Okuhara, K., 273.Okumura, T., 333.Olah, G., 230.Oltih, G. A., 85, 161, 209.Olaitan, S. A., 350.Olavesen, A. H., 352.Oliver, J. P., 87.Oliveto, E. P., 209, 325,326, 327, 330.Ollk, W. D., 282, 283.Ollivier, C., 408.Olofson, R. A., 269, 308.Olovsson, I., 463.Olsen, E.D., 446, 448.ROlson, C., 441.Olson, E. C., 424, 431.Olsson, S., 160.Olya, A., 447.Onak, T. P., 82.Oncescu, T., 178.O’Neal, M. J., 451.Oneson, I., 372.Onoe, T., 430.Onsager, L., 56.Onstott, E. I., 440.Onyszchuk, M., 83, 84, 88,O-ohata, K., 141.Oomori, S., 301.Ooshika, Y., 143.Oosterbaan, R. A., 321.Opdovskii, A. A., 101.Opitz, G., 240.Orazi, 0. O., 299.Orekhovitch, V. N., 367,Orgel, L. E., 69, 103, 105,Orlova, N. D., 42.Orman, S., 165, 231.Oro, J., 279.Orvis, R. L., 299.Osaka, H., 333.Osbond, J. M., 219.Osbond, P. G., 219.Osborn, A. R., 182.Osipov, A. I., 51.Ostapchuk, G. M., 108.Ostermayer, F., 306.O’Sullivan, W. I., 207.Oswald, H. R., 469, 470.Otaki, T., 45.Otsuka, H., 430.Ott, K.-H., 242.Ottensoser, M., 403.Otterson, D.A., 437.Otto, P. P. H. L., 246.Otto, S., 205.Oubridge, J. V., 100.Ouellette, R. J., 175.Oughton, J. F., 325, 326.Ourisson, G., 194, 256, 258,Ovenall, D. W., 87.Overend, W. G., 337, 338,Overton, K. H., 250.Owen, L. N., 343.Owston, P. G., 129, 457.Ozhigov, E. P., 402.Ozolins, M., 418.0~~ei11, c. E., 45.91.369.128.323, 328.341.Paabo, M., 400.Paciik, J., 339.Pace, R. J., 37, 82.Pachler, K., 467.Pachter, I. J., 272, 291.Pachucki, C. F., 450.Packer, J., 162.Paddock, N. L., 98.Padgett, A., 27, 139, 142.Padwa, A., 209, 222.Page, I. H., 314.Paine, D. H., 97.Painter, T. J., 352.Pajak, Z., 73.Paldus, J., 158.Palei, P. N., 417, 421.Palit, S.R., 153.Palland, R., 197, 205.Palmer, W. G., 97.Palmere, R. M., 291, 325.Panchenko, Y. M., 454.Pande, K. C., 161.Pandraud, H., 477.Panek, A., 406.Panizzi, L., 256.Pankova, M., 177.Pansare, V. S., 431.Pant, L. M., 471.Pantony, D. A., 399.Paoloni, L., 145.Parbrook, H. D., 29, 31.Parker, R., 142, 158.Park, G. J., 252.Parker, A., 400.Parker, A. C., 322.Parker, A. J., 164, 171, 173.Parker, C. A., 434,435.Parker, G. A., 91, 175.Parker, J. G., 29, 50.Parker, W., 251.Parkinson, A. R., 224.Parks, J. M., 140.Parmentier, G., 311.Parnes, Z. N., 231.Parpiev, N. A., 468.Parr, R. G., 27, 139, 140,Parrk, M., 104.Parrish, F. W., 348, 351.Parrkh, R. V., 132.Parry, E. H., 46.Parry, E. P., 422.Parry, R.W., 81.Parshall, G. W., 114.Parsons, C. G., 210.Parsons, T. D., 84.Parthasarathy, P. C., 256.Partich, R., 144.Partridge, C. W. H., 383.Paschkes, B., 414.Pasternak, R. A., 475.Pasto, D. J., 95, 201, 242.PQsztor, L., 404, 411.Patai, S., 176, 337.Pataki, G., 304.Patch, R. W., 46.Patchornik, A., 303, 304,Patel, H. P., 266.Patelli, B., 324.Paterson, W. G., 83, 84.Patrick, C. R., 224.142, 143.308506 INDEX OF AUTHORS’ NAMESPatterson, W. L., jun. 46.Paudler, W. W., 272.Paul, A., 251.Paul, I. C., 260, 478.Paul, M. A., 154, 156.Paul, R., 307.Paulik, F., 452.Paulin, D., 90.Pauling, L., 17, 317.Pauling, P., 464, 466.Pauling, P. J., 104, 113,Paulsen, H., 338.Paulsen, S. R., 261.Pauncz, R., 17, 21, 142,144, 145, 194.Paunovi6, M.M., 424.Paunovid, N. M., 424.Pausacker, K. H., 271.Pauson, P. L., 117, 234,Payette, G., 145.Payne, D. S., 96.Payne, G. B., 202.Peach, M. E., 85, 101.Peacock, R. D., 105, 469.Peacock, T. E., 145, 146,Peaker, F. W., 437.Pearson, B. D., 234.Pearson, D. E., 153.Pearson, G. C., 163.Pearson, I. M., 126.Pearson, R. G., 104, 106,Pearson, W. A., 226.Peat, S., 341, 350, 351.PEcen?, R., 443.Pechet, M. M., 209, 329.Pecile, C., 130.Pecsok, R. L., 125.Pedersen, B., 127.Pedersen, C., 343.Peekema, R. M., 424.Peeling, M. G., 162.Peets, E. A., 430.Pekeris, C. L., 15.Pelc, B., 324.Pelizzoni, F., 240.Pella, E., 431.Pellan, F., 73.Pellegrini, G. U. M., 426.Pelletier, S. W., 297, 298.Penarowski, M., 417.Penfold, B.R., 472.Penneman, R. A., 122, 135.Pepinsky, R., 91.Percival, E. 350, 351, 352.Peri, J. B., 45.Perkin, W. H., 267.Perl, H., 94.Perlin, A. S., 339, 346, 349.PBron, F. G., 334.Perone, S. P., 446.Perrino, A. C., 212.Perry, M. B., 338, 339, 342.123, 132.237, 240.158.107.Perry, S. G., 182.Perry, W., 448.Person, W. B., 39, 101, 102.Perthel, R., 105.Pesaro, M., 299.Petch, H. E., 456.Peterhans, J., 108.Peterlin, A., 77.Peters, C. R., 460.Peters, D., 147, 231.Peters, D. G., 427.Peters, F. M., 86.Peters, R. A., 222.Petersen, R. C., 164, 173,Peterson, A., 122.Peterson, A. H., 238.Peterson, H. J., 162.Peterson, J. O., 200.Peterson, P. E., 243.Peterson, S. W., 454, 455,Petit, G.R., 200.Petrakis, L., 62.Petrie, M., 462.Petrikova, M. N., 401.Petrov, A. A., 36, 41.Petrov, A. D., 87.Petrow, V., 209, 324, 326,Petru, F., 248.Petrucci, R. H., 45.Petruska, J., 17, 146.Petry, R. C., 94, 210.Petterson, L. L., 83.Pettit, R., 114, 275.Pfeil, F., 183.Pfleiderer, W., 280, 281.Pfluger, C. E., 474.Philbin, E. M., 68, 283.Phillip, H., 179.Phillips, D. C., 317, 453.Phillips, D. K., 323.Phillips, G. O., 336.Phillips, J. N., 153.Phillips, J. R., 93.Phillips, W. D., 69.Phillipson, P. E., 25.Philpott, P. G., 219.Photaki, I., 306.Piatak, D. M., 200.Pickart, S. J., 457.Pickering, W. F., 433.Pickert, S., 456.Piel, W., 340.Pierce, J. V., 313.Pierce, T. B., 404.Pierdet, A., 332.Pierog, S., 388.Piez, K.A., 369, 378.Pike, R. M., 89.Pilar, F. L., 145, 166, 265.Pillai, C. N., 204.Pimentel, G. C., 43.Pimlott, P. J. E., 306.Pinder, A. R., 298.178.457.329.Pine, M. J., 390.Pineau, P., 37.Pines, H., 204, 207, 221,Pinhey, J. T., 288.Pink, P., 207.Pinkerton, J. N., 78.Pinkus, A. G., 284.Pinsker, Z. G., 127.Pintar, M., 77.Pinto, I. P., 407.Pintschovius, U., 263.Piper, E. A., 410.Piper, J. U., 235.Piper, S. H., 220.Pirkle, W. H., 95, 201.Pischtschan, S., 91.Pitcher, E., 111, 119.Pitra, J., 332.Pittet, A. O., 335, 340.Pitzer, K. S., 43, 141.Placeway, C., 290.Plaschil, E., 270.Platas, O., 17, 456.Platonova, A. V., 332.Platt, J. R., 145.Plaut, G. W. E., 393.Plesske, K., 236.Plettinger, H.A., 121, 470.Pliskin, W. A., 44, 46.Plotner, G., 203.Plostnieks, J., 70.Plovhan, R. A., 443.Pluvinage, P., 19.Plyusnin, V. G., 159.Pocchiari, F., 406.Pocker, Y., 190.Podall, H. E., 108.Poddubnaya, S. S., 168.PoduBka, K., 300.Pohl, F. A., 445.Pohl, G., 276.Pohlmann, J. L. W., 228.Poling, G. W., 41.Polonsky, J., 258, 301.Poltorak, B. A., 49.Pomerantsev, N. M., 68.Pommer, H., 216.Pompowski, T., 408.Pool, K. H., 424.Popa, G., 421.Pope, G. A., 228.Popiel, W. J., 337.Popjak, G., 353, 354, 359,364, 365.Pople, J. A., 55, 56, 67, 138,140, 141, 142, 149, 150.Popov, A. I., 39, 101.Porai-Koshits, M. A., 468.Porath, J., 316.Porsche, F. W., 451.Porte, A. L., 61, 130.Porter, C., 448.Porter, G., 51, 145.Porter, J.W., 357, 361.Porter, R. F., 84.239INDEX OF AUTHORS’ NAMES 507Posgay, E., 418.Post, B., 455, 462, 475.Post, H. W., 122.Postlethwaite, J. D., 133.Potenza, F., 433.Potts, K. T., 266.Pouradier, J., 372.Povondra, P., 415.Powell, D. B., 134.Powell, D. L., 89.Powell, H. M., 105, 132,134, 465, 466.Powell, J. W., 215.Powers, J. C., 163.Powles, J. F., 78.Pracejus, H., 192.Pradhan, S. K., 260.Praill, P. F. G., 274.Prakashi, S. C., 289.Prat, M.-T., 474.Pratt, E. F., 202, 203.Pratt, L., 69, 113, 114.Preece, E. R., 449.Pregaglia, G. F., 221.Prehesnik, A., 76.Preisman, R., 159.Prelog, V., 197, 297.Preston, C., 348.Preston, D. R., 227, 228,Prestridge, H. B., 108.Pretorius, V., 406.Preuss, H., 26, 138.Prey, V., 346.PFibil, R., 415, 425.Price, C.C., 171, 276.Price, R. G., 351.Price, W. C., 38, 44.Prins, W., 346.Prinzbach, H., 235.Pritchard, D. E., 69.Pritchard, H. O., 18, 33, 46,Pritchard, J. P., 67.Pritchard, R. A., 344.Privat de Garilhe, M., 314,ProchBzka, Z., 335.Prohaska, C. A., 68.Proks, I., 451.Propst, R. C., 419.Prosser, J. H., 164.Prosser, T. J., 171.Prout, C. K., 105, 134.Provaznik, J., 399.Prue, J. E., 76.Przybylska, M., 478.Ptits$n, B. V., 449.PuEar, Z., 408.Puchta, R., 347.Puckett, R. T., 221.Puisieux, F., 292.Pulley, A. O., 349.Pullin, A. D. E., 35, 36, 43,Pullman, A., 148.233.51, 234.316.45.Pullman, B., 145, 146, 148.Pummer, W. J., 224.Pungor, E., 428.Purdy, W. C., 417, 444.Puri, D.M., 123.Purlee, E. L., 76.PUG, J., 430.PuskAs, I., 193, 341.Putnam, R. E., 216.Pyszora, H., 75.Quail, J. W., 132.Quartermain, L. A., 98.Quilbery, M., 74.Quinchon, J., 347.Quitt, P., 257, 297.QUO, S.-G., 208.Raab, G., 89, 93.Raben, M. S., 316.Rabenau, A., 469.Rabin, B. R., 320.Rabinovitch, B. S., 34, 178,Rabinowitz, J., 302.Rabinowitz, J. L., 302.Rachlin, A. J., 219.Rachmeler, M., 385.Radda, G. K., 158, 162.Radell, J., 221.Radley, J. R., 434.Radmacher, W., 430.Ratz, R., 97.Rai, J., 398.Rainer, G., 279.Raisch, M., 434.Rajic, M., 328.Ra,jBner, M., 301.Rakowska, E., 446.Ralph, R. D., 158.Ralston, H., 407.Ramachandran, G. N., 375.Ramachandran, J., 316,Ramachandran, L. K., 303.Ramachandran, P.K., 254.Ramage, R., 251.Ramakrishnan, V., 165.Raman, S., 455.Ramaneshnan, S., 292.Ramirez-Muiioz, J., 433.Ramsay, D. A., 145.Ramsay, N. F., 150.Ramsay, 0. B., 170.Ramsey, B. G., 234.Ramstad, R. W., 410.Rand, M. C., 399.Randall, E. W., 70.Randell, D. R., 283.Ranneva, Yu. I., 160.Ransil, B. J., 26, 27, 139.Rao, A. S., 251.Rao, B. D. W., 55.Rao, D. V., 211, 224.Rao, G. P., 417.238.Rao, K. N., 155.Rao, P. S., 175.Rao, S. P., 341.Raphael, R. A., 218, 251.Rapoport, H., 285, 288.Rasburn, J. W., 244.Rasmussen, S. E., 98.Rassat, A., 248.Rastrup-Andersen, J., 166.Ratney, R. S., 237.Rauch, G., 220.Rausch, M. D., 237.Ravens, D. A. S., 202.Raw, I., 353.Rawlinson, D. J., 163.Ray, N. H., 100, 221.Ray, P., 103.Ray, S.K., 97.Ray, T. C., 40.Raymond, S., 408.Razikovskaya, S. V., 121.Read, A. W., 33.Read, G., 214.Rechnitz, G. A., 427.Recondo, E., 339.Recourt, J. H., 219.Redcliffe, A. H., 220.Reddy, G. S., 61, 64, 66, 76,R6dei, L., 19.Redfern, J. P., 452.Redman, J. D., 122.Redords, R., 248.Reed, H. W. B., 109.Rees, C. W., 209, 337.Rees, D. A., 351.Rees, R., 263, 332, 333.Rees, R. M., 450.Reese, E. T., 345, 351.Reeves, L. W., 61, 66, 74,Reeves, R. E., 337.Reeves, R. R., 53.Reggel, L., 201.Reichstein, T., 218, 332,333, 339.Reid, C., 74, 165.Reid, I. K., 129.Reid, J., 342.Reid, W., 307.Reiding, D. J., 205.Reilley, C. N., 424.Reilly, C. A., 56, 58, 76.Reimann, H., 209, 330.Reimlinger, H., 210, 266.Rein, J.E., 404, 405, 448,Reinheimer, J. D., 164.Reinmuth, W. H., 427,444,Reinshagen, H., 293.Reisch, J., 263.Reisman, A., 125.Reisse, J., 247.Reitsema, R. H., 430.Remanick, A., 193, 245.265.77, 194.449.445508 INDEX OF AUTHORS’ NAMESRemport, I., 414.Remy, H., 124.Renfrow, W. B., 265.Renk, E., 238.Repinsky, R., 175.Reppe, W., 222.Resnick, P. R., 213.Reusch, W. H., 258.Reusche, W., 286.Reutov, 0. A., 108, 168,Reynolds, G. F., 444.Reynolds - Warnhoff, P.,193, 245.Riad, Y., 179.Ricci, E., 447.Rice, H. E., 238.Rich, A., 375, 377.Richards, F. M., 320.Richards, J. H., 35, 41, 60,117, 151, 157, 236, 276.Richards, R. E., 55, 68, 69,73, 322.Richards, S., 127.Richardson, A. C., 342.Richardson, D.B., 178.Richardson, E. G., 30.Richardson, J. W., 151.Richardson, M. L., 418.Richardson, S. H., 287.Richert, H., 94.Richmond, A., 53.Richter, P., 221.Richtmyer, N. K., 340.Rickborn, B., 170.Ricker, E., 83.Ridd, J. H., 154, 160, 176.Riddick, J. A., 424.Riddle, J. R., 82.Rieche, A., 206, 216.Ried, W., 265, 266.Riedel, O., 430.Rieman, W., 409.Riemschneider, R., 190,Riesel, L., 100.Riess, C., 402.Rigamonti, A., 78.Riganti, V., 476.Rigaudy, J., 242.Rigden, J. S., 81.Rigler, N. E., 335.Riley, B. J., 257.Riley, D., 169.Riley, T., 159.Rimshaw, S. J., 405.Rinderknecht, H., 339.Rinehart, K. L., jun., 342.Ring, M. A., 88.Ringold, H. J., 195, 335.Riniker, B., 314.Rink, J. P., 49, 52.Rink, M., 418.Ripamonti, A., 33.Ripperger, H., 297.178.Rhind-Tutt, A.J., 176, 337.212.Ritchie, A. C., 326.Ritchie, E., 288.Rittel, W., 305, 313.Rittenberg, S. C., 287.Ritter, A., 305.Ritter, D. M., 88.Ritter, Z. W., 17, 21.Rivas, C., 206, 229.Rivera, M. E. C., 197.Robben, F., 29, 30, 46.Robbins, P., 448.Robbins, W. J., 389, 392.Roberson, W. E., 36.Roberts, B. W., 221.Roberts, H. L., 99, 100,221.Roberts, J. C., 276.Roberts, J. D., 55, 59, 67,Robertson, A. V., 278.Robertson, G. B., 466, 473.Robertson, J. M., 24S, 253,260, 292, 475, 477, 478,479.Robertson, R. E., 155, 156,177, 184.Robertson, W. A. H., 270.Robinson, B., 278.Robinson, C. H., 209, 325,Robinson, E. A., 100.Robinson, G., 113, 464.Robinson, G. B., 123.Robinson, G.W., 39.Robinson, H. L., 100.Robinson, J. M., 26.Robinson, J. W., 437, 438.Robinson, P. D., 24.Robinson, P. S., 122.Robinson, R., 217,218, 286.Robinson, R. J., 452.Robinson, W. T., jun., 418,Robnett, O., 437.Robson, P., 224.Rochester, C. H., 165.Rochow, E. G., 77.Roddy, F., 395.Rodewald, P. G., 91, 175.Rodigin, N. M., 159.Rodnova, G. G., 442.Roe, D. K., 441.Roe, E. T., 219.Roev, L. M., 45, 46.Rogan, J. B., 197.Rogasch, P. E., 41.Rogers, L. B., 423.Rogers, M. T., 63.Rogers, N. A. J., 254.Rogers, R. N., 451.Rogers, V., 233.Rogier, M. S., 247.Rogozinski, J. R., 200.Rohrbaugh, P. E., 164.Rolf, R. F., 405.Rolle, M., 373.Romanet, R., 36.238, 240.326, 327.426.Romers, C., 474.Rsmming, C., 463.Romo, J., 253.Romo de Vivar, A., 253.Rondestvedt, C.S., 273.Rook, A., 190.ROOR. O., 243.ROG -laan, C. C. J., 11, 12,Rorem, E. S., 403.Rosculet, G., 307.Rose, F. A., 351.Rose, J. D., 222.Rosen, H., 371.Rosen, P., 207.Rosen, W. E., 291.Rosenbaum, J., 175.Rosenberg, E. S., 182.Rosenblatt, G. M., 103.Rosenbrook, W., jun., 400.Rosendahl, K., 275.Rosene, C. J., 287.Rosenmund, K.-W., 206.Rosevear, J. W., 321.Rosowsky, A,, 144.Ross, C. A., 320.Ross, H. H., 404, 449.Ross, I. G., 139.Ross, M., 466.Ross, S. D., 164, 173, 178.Ross, Y. F., 77.Rossetto, O., 176.Rossi, C., 406.Rossi, C. J., 204, 215.Rossi-Fanelli, A., 395.Rossmanith, K., 121.Rossmann, M. G., 454.Rossotti, F. J. C., 183, 266.Rost, G.A., 446.Roth, M., 267.Roth, W., 29, 30, 51.Roth, W. L., 457.Rothweiler, W., 408.Ritzler, G., 153.Roubinek, L., 240.Rouclier, A. J., 351.Roumi-Laridjani, M., 222.ROUX, M., 27.Rover, I(. R., 342.Rowan, R., jun., 410.Rowe, G. A., 120, 127.Rowlands, R. J., 406.Rowlinson, J. S., 34.Roy, S. K., 289.Royer, D. J., 127.Rubalcava, H., 46.Rubin, H., 432.Rubinfeld, J., 220.Ruby, A., 106.Rudinger, G., 47.Rudinger, J., 300, 301, 305,306, 310, 315.Rudloff, V., 317.Rudolph, G., 95.Ruckemann, H., 111.Ruedenberg, K., 143.15INDEX OF AUTHORS’ NAMES 509Ruegg, R., 217.Rueff, L., 353.Riihlmann, K., 305, 410.Riill, T., 328.Ruf, H., 89.Ruff, J. K., 81, 86.Ruidisch, I., 91, 92.Ruiter, A., 153.Rukwied, M., 281.Rundel, W., 242.Rundle, R.E., 101, 126,Rundqvist, S., 461.Runeberg, J., 254.Ruoff, P. M., 341.Rupprecht, A., 64.Rusina, A., 105, 201.Russell, D. R., 134.Russell, G. A., 169.Russell, R. C., 283.Rust, F. F., 119.Rutkin, P., 193.Rutledge, P. S., 257, 297.RfiziiEka, J., 405, 449.Ryabov, A. N., 128.Ryadnina, A. M., 432.Ryan, T. D., 132, 468.Ryce, S. A., 410.Rychlik, I., 315.Ryder, H. N., 176.Rydon,H. N., 176,313,321.Ryhage, R., 219.Ryland, L. B., 426.Ryschkewitsch, G. E., 83.Ryser, G., 217.Ryss, I. G., 85.Ryzhova, T. V., 453.Rzeszotarska, B., 306.132, 468, 469, 470.Sa, A., 403.Sabo, E. F., 325.Sacco, A., 130.Sacher, E., 162.Sachindra Kumer Datta,Sachindra Nath Saha, 401.Sachs, L. M., 12, 22.Sackman, E., 59.Sadeh, T., 304.Sado, A., 145.Sadowski, A., 87.Saegebarth, K.A., 198.Saeman, J. F., 407.Saint-Blancard, J., 408.St. Guttmann, 313, 314,315, 316.Saint John, L. E., 429.Saito, E., 99.Saito, T., 341.Saito, Y., 134, 467.Saji, A., 83.Sakamoto, M., 26, 153.Sakan, T., 287.Sakashita, A., 332.Sa.kurai, H., 423, 424.401.Sakurai, K., 472.Salem, L., 143, 144.Salesin, E. D., 413.Salfield, J.-C., 237.Salisbury, L., 203.Salkoff, M., 51.Sallach, R. A., 122.Salter, R., 31.Salton, M. R. J., 350.Samann, E., 70.Samartseva, A. G., 440.Sambucetti, C. J., 420.Samitov, Y. Y., 68.Samsonov, G. V., 121.Samuel, D., 183.Sanchez, 33. B., 326.Sand, D. M., 349.Sandberg, R., 181, 249.Sanders, J., 449.Sandorfy, C., 145, 148.Sandrin, E., 316.Sangal, S.P., 416.Sanger, F., 321.Sanhueze, A. C., 82.Sant, B. R., 425.Sant, S. B., 425.Sant,arella, G., 232.Santhanam, K. S. V., 424.SBra, J., 415.Saraiya, S. C., 420.Sarasohn, I. M., 279.Sardinas, J. L., 334.SBrosi, S., 402.H. Sarrafizadeh, R., 225,Sasaki, Y., 127, 253.Sasha, B., 259.Sasin, G. G. S., 221.Sasin, R., 221.Sasisekharan, V., 375.Satchell, D. P. N., 160.Sato, H., 92, 93.Sato, T., 122.Sato, Y., 36, 322, 335.Satoh, D., 333.Saturno, A. F., 27.Sauer, J., 269.Sauers, R. R., 202,245,250.Saumagne, P., 37, 41.Saunders, F. C., 165, 231.Saunders, M., 56, 70.Saunders, R. A., 450.Saunders, W. H., 144.Saunderson, C. P., 478.Savage, C. A., 132.Saville, B., 184, 415.Savory, J., 102, 432.Savvin, S.B., 435.Sawatsky, H., 168.Sawicki, E., 403.Sawistowska, M., 201.Sawyer, A. K., 92.Scaife, D. E., 104, 124.Scanu, A., 377.Scargill, D., 94, 111.Scatt,urin, V., 456.228.Schaad, L. J., 143.Schaal, R., 154.Schaap, L. A., 207, 221.Schachnow, M., 403.Schafer, H., 125, 126, 469.Schaefer, T., 56, 71, 73, 158.Schaefer, W. P., 125,423.Schaeffer, G. W., 80;Schaeffer, R., 83, 84.Schafer, W. R., 203.Schaffernicht, W., 172.Schaffner, C. P., 335.Schaffner, K., 330, 331.Schaller, H., 267, 307.Schaub, R. E., 324.Schaumann, C. W., 229.Scheben, J. A., 205.Schejtanow, C., 423.Schellenberger, A., 272.Schellmann, J. A., 190,302.Schemjakin, M. M., 310.Schenk, G. H., 418.Schenk, G. O., 224.Schenker, E., 198.Schenker, K., 212.Scheraga, H.A., 305.Scheringer, C., 126, 467,Scherr, C. W., 17, 20.Scheuer, P. J., 292.Schiedt, U., 379.Schiess, P. W., 254.Schiff, H. I., 53.Schildknecht, H., 220.Schindewolf, U., 447.Schindler, D., 218.Schindler, O., 333, 339.Schlafer, H. L., 107, 123,Schlenk, H., 349.Schleyer, M., 371.Schleyer, P. von R., 62,177.Schliep, H. J., 280.Schlossea, M., 215.Schluter, E. C., 422.Schmall, M., 408.Schmeil, F., 126.Schmeising, N. H., 144.Schmeisser, M., 101.Schmid, C., 365.Schmid, H., 292, 293, 294,Schmid, O., 286.Schmidbaur, H., 89, 91,Schmidlin, J., 334.Schmidt, H., 444.Schmidt, M., 89, 91, 92.Schmidt, P., 279.Schmidtke, H.-H., 26.Schmitt, F. O., 368, 371.Schmitt, R., 123.Schmitz, E., 206, 216, 261,Schmir, G.L., 303.Schnabel, E., 316.469.172.478.92.262510 INSchneider, H., 66.Schneider, H. J., 221.Schneider, J., 156.Schneider, R., 448, 464.Schneider, W. G., 55, 64,66, 71, 73, 76, 149, 157,158.Schnering, H. G., 134, 135,469.Schobinger, U., 237.Schober, G., 444.Schollkopf, U., 221.Schollkopf, V., 171.Schollner, R., 202.Schoen, L., 81.Schoniger, W., 429.Schofield, C. K., 166.Schofield, D., 32, 50.Schofield, J. A., 313.Schogt, J. C. M., 219.Scholes, P. H., 445.Scholz, C. R., 324.Scholz, H., 126.Schomaker, V., 232.Schonbaum, G. R., 184.Schopfer, W. H., 389, 392.Schoo, W., 206.Schott, G., 89.Schott, G. L., 50.Schramm, G., 319.Schrauzer, G. N., 112, 113,Schreiber, J., 261, 299.Schreiber, K., 297.Schreiber, T.P., 433.Schrenk, W. G., 409.Schroder, C., 270.Schroeder, C. W., 348.Schroder, G., 233.Schroeder, H.-D., 293, 478.Schroder, W., 246.Schroeder, W. A., 317.Schrohenloher, R. E., 375,Schubert, F., 81.Schubert, W. J., 237.Schuch, A. F., 460.Schudel, P., 217, 299.Schuerch, C., 346.Schug, K., 87.Schulek, E., 414.Schulenberg, J. W., 287.Schuller, F., 39.Schuller, W. H., 256.Schulte, K. E., 263.Schultz, H., 203.Schultze, C., 133.Schulz, R. C., 220.Schulze, J., 153.Schwartz, E. T., 306, 315.Schwartz, G. M., 264.Schwartz, H., 333.Schwartz, H. M., 16.Schwartz, W. T., jun., 122.Schwarz, C., 411.Schwarz, J. C. P., 343.222.376.EX OF AUTHORS’ NAMESSchwarz, V., 321.Schwarzbach, F., 126.Schwarzenbach, G., 103.Schwenckendiek, W.J.,Schwiersch, W., 269.Schwieter, U., 217.Schwink, I., 382.Schwochau, K., 127.Schwyzer, R., 305, 306,307, 310, 311, 313, 314,316, 317.Sciaky, R., 324, 326.Scmutzler, R., 131.Scott, A. F., 399.Scott, D. A., 170.Scott, F. A., 424.Scott, F. L., 229.Scott, J. M. W., 159, 177.Scott, P. G. W., 409.Scott, S. J., 410.Scott, T. A., 345, 388.Scribner, W. G., 425.Scrocco, E., 23.Searle, H. T., 97, 98.Searles, S., 38.Sebera, D. K., 106.Secci, M., 192.Sederholm, C. H., 62, 66,68, 194.gedivec, V., 443.Seel, F., 131.Seeliger, A., 339, 342.Segnini, D., 277.Segovia, R., 327.Seibl, J., 304.Seidel, B., 116.Seidel, M., 269.Seifert, H.-J., 123, 124,130, 469.Seifter, S., 373, 374.Seiler, H., 408.Seip, D., 235.Seki, T., 304.Selig, H., 127, 128.Selleri, R., 411.Sellers, D.E., 422, 444.Sello, S. B., 348.Selman, L. H., 176, 337.Seltzer, a., 207.Semmer, R. T., 105.Semmlinger, W., 113.Senko, M. E., 455.Sensabaugh, A. J., 426.Senti, F. R., 345, 349.Sepichowska, A., 122.Serres, C., 229.Setser, D. W., 178, 238.Seubert, W., 353.Sexson, I<. R., 349.Seyferth, D., 59, 89, 93,Shabtai, J., 239.Shafer, P. R., 67.Shah, V. R., 282.Shahak, I., 222.222.95, 208.Shaheen, D. G., 432.Shain, I., 441,445, 446.Shallenberger, R. S., 346.Shamgar, A. H., 336, 341.Shamma, M., 287, 299.Shapiro, D., 219.Shapiro, H., 108.Shapiro, I., 66, 85, 451.Shapiro, R., 275.Sharkey, W.H., 216.Sharma, B., 421.Sharma, B. D., 475.Sharma, S. K., 341.Sharman, S. H., 243.Sharp, D. W. A., 100, 104,Sharpe, A. G., 132.Shars, C. M., 240.Shatenshtein, A. I., 160.Shaw, B. L., 104, 109, 114,120, 236.Shaw, D., 278.Shaw, D. C., 321.Shaw, G., 300.Shaw, R. A., 97.Shaw, S. R., 431.Shchedrin, B. M., 454.Shchukarev, S. A., 128.Shechter, H., 179, 206, 210,Sheehan, J. C., 307, 310.Sheffield, J. C., 450.Sheft, I., 122, 176, 337.Sheldrick, B., 335.Shelley, R. N., 450.Shenderetskaya, E. V., 130.Sheppard, N., 42, 44, 45,46, 56, 59, 66, 68, 114,193.Sheppard, R. C., 300, 301,302.Sheridan, J., 208.Sherman, H., 355.Sherman, W. F., 38, 44.Shetlar, M. D., 412.Shibnev, V.A., 375.Shibuya, I., 459.Shields, F. D., 30.Shields, J. E., 306.Shigematsu, T., 404.Shigorin, D. N., 36.Shih-Chuen Chia, A., 166.Shih-En Hu, 193.Shiihara, I., 122.Shillaker, B., 177.Shilov, E. A., 163.Shim, K. S., 246.Shima, T., 298.Shimada, A., 472.Shimanouchi, T., 36.Shimaoka, A., 333.Shimazona, N., 394.Shimizu, H., 56, 59, 74.Shindo, K., 45.Shiner, V. J., 155, 156,134.242.182INDEX OF AUTHORS’ NAMES 51 1Shingu, K., 190.Shiono, R., 475.Shipikiter, V. O., 367, 369.Shirai, H., 445.Shirane, G., 456, 457.Shirley, R. L., 228.Shishkov, Y. D., 101.Shkol’nikova, L. M., 106.Shlyapochnikov, V. A., 435.Shome, S. C., 411, 412.Shoolery, J. N., 193, 252,Shore, V. C., 317.Shorley, P. G., 313.Shorter, J., 179, 196.Shostakovski, M.F., 36.Shott, J. E., jun., 435.Shrivastava, H. N., 471.Shugam, E. A., 106.Shuiken, N. I., 207.Shuler, K. E., 33, 51, 54.Shuler, W. E., 68, 76.Shull, E. R., 277.Shull, G. M., 334.Shull, H., 10, 18, 21, 24, 25,Shults, W. D., 423.Shuvalov, L. A., 458.Shuvalova, E. V., 36.Shygorin, D. N., 68.Sibbing, E., 125.Sicher, J., 177, 180, 243,Siddalingaiah, K. P., 283.Siddall, T. H., 68.Siddons, P. T., 68, 217.Sidisunthorn, P., 192.Sieber, P., 305, 311, 313.Siemianowska, I., 408.Sienko, M. J., 127.Sigilla, J., 102.Sikl, D., 332.Silberman, H. C., 336.Siliprandi, N., 395.Silver, A. H., 77.Silver, B., 183.Silver, M. S., 238.Silverman, J. N., 17, 22,Silverman, L., 122.Silverthorn, M. E., 79.Silverton, J.V., 79, 124,127, 128, 466.Silvestroni, P., 11 1.Silvidi, A. A., 76.Sim, G. A., 249, 260, 292,293, 471, 477, 478, 479.Simamura, O., 151.Simchen, G., 172.S h e , J. G., 262, 478.Simek, M., 430.Simmonin, M. P., 441.Simmons, G. L., 474.Simon, A., 100.Simon, H., 280, 336.Simon, Z., 107.277, 287.146, 148.301.456, 470.Simonetta, M., 145, 147.Simonoc, V. J., 454.Simonoff, G., 102.Simons, D. M., 166.Simons, M. C., 178.Simonsen, J. L., 249.Simonsen, S. H., 474.Simova-Filippova, L., 416.Simpson, P. G., 461.Simpson, W. B., 93.Sims, R. P. A., 436.Sinclair, V. C., 475.Sinex, F. M., 378.Singer, K., 25.Singh, E. J.. 407.Singh, K. P., 286.Sinlia, S. K., 63, 151, 412.SipoB, F., 177, 180.Sisido, K., 228, 253.&&e, V., 451.Sittig, E., 30.Sixma, F.L. J., 159, 206.Sjoberg, B., 302.Sjoholm, I., 302.Sjoquist, J., 304.Sjovall, J., 322.Skancke, P. N., 196, 247.Skaric, V., 298.Skattebol, L., 214, 244.Skeggs, H. R., 395.Skeggs, P. K., 394.Skell, P. S., 179, 191, 238.Skinner, C. R., 47.Skinner, G. B., 49.Sklar, N., 455.Sklyarenko, I. S., 452.Slade, P., 180.Slater, C. D., 159.Slater, G. P., 202, 324.Slater, J. C., 9.Slates, H. L., 328.Slaugh, L. H., 170.Sleddon, G. J., 86.Slee, L. J., 449, 450.Sleight, A. W., 127.Sloan, A. D. B., 218.Sloan, M. F., 174.Slomp, G., 75.Slota, P. J., 97.Slovetskii, V. I., 435.Sly, J. C. P., 324.Smales, A. A., 445, 447,449, 450.Small, T., 282.Smart, N. A., 307.Smeby, R.R., 314.Smidt, J., 236.Smit, W. M., 420.Smith, A. G., 88.Smith, B. H., 190.Smith, C. R., jun., 218.Smith, D. E., 444.Smith, D. L., 115, 421, 441,Smith, D. L. G., 433.Smith, D. R., 97.465.Smith, E., 299.Smith, E. L., 317, 320, 321.Smith, E. M., 158.Smith, F., 349.Smith, F. A., 29, 316.Smith, G. F., 277, 278, 292.Smith, G. G., 186.Smith, G. H., 117, 237.Smith, H., 256.Smith, H. G., 64, 454.Smith, I. C., 66, 158.Smith, J. A., 51.Smith, J. A. S., 76.Smith, J. D., 86.Smith, J. E. W. L., 467.Smith, J. K., 90.Smith, J. V., 453.Smith, L. L., 329.Smith, M. L., 155.Smith, P. A. S., 279.Smith, P. W., 126.Smith, R. A. D., 422, 431.Smith, S. G., 173.Smith, T. E., 278.Smith, W. B., 175.Smolders, R.R., 252.Smolinsky, G., 179.Smullin, C. F., 429.Smythe, L. E., 398.Snatzke, G., 327, 333.Snaprud, S. I., 184.Snell, B. K., 311.gnell, E., 383.Snobl, D., 429.Snyder, C. H., 199, 216.Snyder, H. R., 61, 197, 243,Snyder, L. R., 406, 451.Snyder, R. G., 470.Snyder, R. H., 264,Snyder, W. H., 171.Sobel, A. E., 378.Sobolov, N. N., 48.Soborovskii, L. Z., 98.Soderback, E., 264.Sokoloski, E. M., 49.Sokolov, N. D., 51.Sokolov, W. I., 168.Sokolova, L. V., 326.Sokolovsky, M., 304.Sokolowska, T., 306.Solberg, Y. J., 218.Sollick, W. A., 56.Sollman, P. B., 325.Solo, A. J., 298.Solomons, C. C., 372, 373.Soloski, E. J., 92.Somerfield, G. A., 68.Sommer, L. H., 91, 175.Sondheimer, F., 198, 204,205, 215, 234, 254, 255,299, 328.264.Songina, 0.A., 421.Sonin, A. S., 457, 458.Sonnenberg, J., 173.Soquet, A., 252512 I NSorensen, N. A., 213.Sorm, F., 250,251,252,253,301, 304, 315, 320, 335.Sosnovsky, G., 202.Sotnikov, V. S., 421.SouEek, M., 251.Sourisseau, G., 37, 38.Southwick, P. L., 167.Sovers, O., 23.Sowden, J. C., 342.Sowinski, G., 155, 181, 209.Spackman, D. H., 320.Spalthoff, W., 77.Spandau, H., 100.Sparks, R. A., 144.Spauszus, S., 411.Spayd, R. W., 279.Speakman, J. C., 471.Speed, J. A., 172.Spencer, C. J., 463.Spencer, J. F. T., 350.Spencer, T. A., 299.Spenser, I. D., 206.Sperry, J. A., 167.Spes, H., 221.Spetsig, L. O., 259.Spgvak, A., 402.Spialter, L., 192.Spiegel, H. E., 333.Spielman, J. R., 92.Spiesecke, H., 64, 157, 158.Spingler, H., 332.Spinner, E., 166.Spoerri, P.E., 167.Sprague, J. M., 395.Spring, F. S., 258.Spiihler, G., 306, 315.Squire, W., 46.Squires, C. L., 365.Squirrell, D. C. M., 419,Srinivasan, R., 34, 245,Srivastava, T. N., 91.Staab, H. A., 267.Stace, B. C., 36.Stacey, M., 224, 337, 342,Stachlewska- Wrbblowa, A.,Stackelberg, M. von, 467.Stadler, J., 386.Stafford, S. L., 60, 63, 66,84, 113, 114, 118, 119.Stahl, R. E., 190.Stahl, W. A., 450.Stalinski, B., 77.Stalker, R. J., 48.Stamires, D. N., 45.Stamm, O., 348.Stammreich, H., 102.Stanhk, J., 339.Stanley, R. R., 400.Stanley, T. W., 403.Stanley, W. M., 319.Stansbury, H. A., 262.425, 426, 429, 432.455.343, 345, 347, 352.162.EX OF AUTHORS’ NAMESStansly, P.G., 353.Stanton, G. M., 284.Staples, P. J., 130.Stark, G. R., 302, 320.StiLrka, L., 321, 325.Starobinets, G. L., 409.Starovskii, 0. V., 464.Starratt, A. N., 259.Starf, J., 405, 449.Statham, F. S., 222.Staunton, J., 248.Steeple, H., 477.Steberl, A. E., 361.Stefan, V., 442.Stefanac, z., 190.Stefanovic, V., 335.Stefanovi6, V. D., 345.Steffgen, F. W., 203.Steele, D., 116.Steglich, W., 307.Stehr, C. E., 300.Stein, W. H., 320.Steinberg, D. H., 193.Steinberg, H., 83.Steindler, M. J., 100.Steiner, R. I., 264.Steinmetz, R., 224.Stejskal, E. O., 77.gtempelovh, D., 467.Stenberg, E., 461.Stenberg, V. I., 254.Stender, W., 294.Stenhagen, E., 219.Steniger, M., 259.Stephen, A.M., 352.Stephen, M. J., 151.Stephen, W. I., 402, 411.Stephens, J. A., 207.Stephens, J. D., 59.Stephens, R.,, 224.Stephenson, G. W., 36.Stephenson, L., 325.Stermitz, F. R., 285.Stern, J. R., 353.Sternbach, B., 88.Sternberg, H. W., 201.Sternfeld, M., 165.Sternhell, S., 260.Stetten, M. R., 349.Steven, F. S., 373.Stevens, B., 28, 34.Stevens, L. G., 87.Stevenson, R., 94, 258.Steward, F. C., 301.Stewart, A. L., 20, 22, 26.Stewart, B., 205.Stewart, E. T., 26, 142, 143.Stewart, F. H. C., 225, 401.Stewart, J. M., 132, 178,Stewart, M. A. A., 122.Stewart, R., 153, 175.Stewart, W. E., 70.Steyn-Parv6, E. P., 394.Stille, J. K., 205, 311.Stimson, V. R., 185.454.Stiteler, C. H., 264.Stjernstrom, N. E., 282.Stock, J.T., 417.Stock, L. M., 163.Stockbridge, C. D., 423.Stocker, J. H., 192.Stockmann, H., 414.Stolzle, G., 81.Stoffel, W., 312.Stogova, A. V., 405.Stolow, R. D., 180, 195,248.Stone, F. G. A., 60, 62, 66,67, 69, 84, 93, 95, 104,111, 112, 113, 114, 117,118, 119, 236, 237.Stone, R. H., 185.Stonner, F. W., 323.Stoops, R. F., 435.Storck, J., 408.Stork, G., 207, 244, 251.Story, P. R., 202, 244,Stothers, J. B., 242, 248.Stoudt, T. H., 334.Stoufer, R. C., 129.Stout, G. H., 283.Strain, H. H., 284.Strandberg, B. E., 317.Strasheim, A., 44.Strasser, R., 212.Stratford, M. J. W., 203.Strathdee, J., 152.Strauss, B. S., 388.Strauss, T., 209, 330.Strehlow, R. A., 47, 122.Streitwieser, A., 146, 155.Strem, M.E., 223, 302.Streng, A. G., 99.Stretton, A. 0. W., 317.Stricks, W., 422.Striebeck, A., 267.Striegler, K., 342.Strohl, J. H., 441.Strohmeier, W., 108, 115.Stromatt, R. W., 423.Stromberg, A. G., 442.Strramme, K. O., 61, 66,Stroud, D. R. E., 343, 345,Struchkov, Y. T., 464.Strunz, H., 470.Stuart, C. M., 47.Stuart, J. D., 25.Stubblefield, C. B., 434.Stuck, W., 419.Studer, R. O., 311, 313,Studor, A., 217.Stumpf, P. K., 365.Stupochenko, E. V., 51.Stute, F. B., 101.Stutz, E., 306.Styunkel, T. B., 416.Subba ROS, B. V. S., 451.246.74, 77, 194.347.314INDEX OF AUTHORS’ NAMES 513Suchf, M., 250, 251.Sudzuki, A., 298.Suetka, W., 196.Suemen, Y., 134.Suemone, Y., 468.Sugamori, S. E., 155.Sugden, T. M., 50.Sugihara, J.M., 338.Sugita, T., 192, 238.Suhr, H., 75.Sukupova-Kolkovb, V.,Sulcek, Z., 402.Suld, G., 276.Sumin, L. V., 68.Sumner F. H., 18.Sundaram, A. K., 420.Sundaresan, M., 442.Sundt, E., 297.Sunko, D. E., 238.Surmatis, J. D., 217.Suskind, S. R., 386, 388.Sussmann, A. R., 302.Susuki, S., 245.Susz, B., 73.Sutherland, M. D., 251.Sutin, N., 107.Sutor, D. J., 457.Sutter, J. R., 104.Sutton, L. E., 131.Suvurov, N. N., 326.Suzui, A., 287.Suzuki, H., 146, 151.Suzuki, I., 36.Suzuki, S., 193, 345.Suzuki, T., 456.Suzuoki, J., 390.Svatos, G., 106.Svatos, G. F., 125.Svehla, G., 452.Sveridov, A. G., 48.Svoboda, V., 415, 437.Swain, C. G., 155, 156, 179,Swalen, J. D., 56, 58.Swallow, A. G., 119, 465.Swan, B., 337.Swann, W.B., 410, 442.Swarbrick, R. E., 432.Swart, E. R., 173.Sweeley, C. C., 300.Sweet, A., 169.Swern, D., 219.Swinbourne, E. S., 185.Syavtsillo, S. V., 432.Sfkora, V., 252.Symons, M. C. R., 94, 102,125, 175, 181.Synek, L., 429.Szabb, L., 341.Szabb, P., 341.Szaboles, J., 217.Szejtli, J., 348.Szekeres, L., 414.Szponar, Z., 408.Szwa,rc, M., 225.408.182.Szymanski, H. A., 45, 438.Szymczak, S., 434.’ Tabroff, W., 376.Tabushi, M., 404.Taft, R. W., 153, 158, 164.Taglinger, L., 101.Tapchi, I., 454.Taha, M. I., 340.Tahara,, A., 257.Tai, H., 410.Takahashi, S., 257.Takahashi, T., 423, 424,Takeda, K., 290, 331, 333.Takei, W. J., 456.Takeshita, H., 251.Talaat, M. Y. A., 96.Tamamushi, R., 441.Tamari, M., 279.Tamassy-Lentei, I., 26.Tamborski, C., 92.Tamele, M.W., 426.Tamm, C., 331, 333.Tamres, M., 38.Tamura, M., 211.Tamura, T., 283.Tanabe, M., 325, 327.Tanaka, H., 283.Tanaka, J., 147, 148.Tanaka, N., 441.Tanaka, R., 394.Tanczos, F. I., 33.Tarbell, D. S., 262, 306.Tarrago, X., 102.Taschner, E., 306.Tate, J. M., 92.Tate, M. E., 341.Tatlow, J. C., 224, 225.Tatsuoka, S., 342.Tatsuzaki, I., 77.Tatum, E. L., 383, 385,Taub, D., 68, 322.Taube,H., 76,106,122, 125.Tavale, S. S., 471.Tavares, D. F., 207.Tawney, P. O., 264.Taylor, D. A. H., 256.Taylor, D. R., 295.Taylor, E. C., 272, 275.Taylor, H. T., 215.Taylor, J. B., 285.Taylor, J. C., 467, 478.Taylor, J. H., 45, 87, 463.Taylor, J. W., 224.Taylor, N.E., 469.Taylor, N. H., 103.Taylor, R., 30, 50, 160, 186.Taylor, R. C., 164.Taylor, R. L., 46.Taylor, W. C., 288.Taylor, U7. I., 289.Taylor-Smith, R., 193.Tebby, J. C., 271.445.389.Tedder, J. M., 166, 230,Teloh, D. W., 438.Tempest, W., 29, 31.Templeton, D. H., 87, 124,Templeton, J. F., 268,Templeton, W., 242.Tengler, H., 119.Terasaka, M., 288.Terasawa, T., 331.Terashima, Y., 287.Terenin, A. N., 44, 45,Terent’ev, A. P., 432.Terry, W. G., 302.Teru Yuasa, 436.Tesafik, K., 430.Tesi, G., 97.Tesoro, G. C., 348.Tesser, G. I., 308.Testa, A. C., 427.Testa, C., 409.Testa, E., 206, 262.Theander, O., 338.Theilacker, W., 190.Theobald, C. W., 225.Thiel, M., 270.Thielmann, H., 101.Thier, W., 201.Thoma, R.E., 121.Thomas, A. M., 447.Thomas, D. A., 203.Thomas, G. H. S., 352.Thomas, G. M., 285.Thomas, K.-D., 241.Thomas, L. F., 67, 273.Thomas, M. R., 284.Thomas, P. J., 1$4.Thomas, R. J., 181.Thomas, W., 190.Thomason, P. F., 423.Thome, R., 111.Thompson, A. R., 145.Thompson, C. M., 474.Thompson, D. D., 57.Thompson, E. 0. P., 302,Thompson, H. W., 36, 38,Thompson, J. F., 306.Thompson, M. J., 231.Thompson, S. O., 451.Thompson, T. A., 315.Thompson, W. E., 43.Thomson, J., 349.Thornton, E. R., 156,Thorpe, F. G., 168, 169.Threlfall, T., 299.Thrift, R. I., 289.Thyret, H., 113.Tiberi, R., 327.Tichf, M., 177, 180.Tiers, G. V. D., 56, 67, 70,266.463, 465.46.304.40, 42.179.71, 194, 266514 INDEX OF AUTHORS’ NAMESTietz, A., 357, 359, 364,Til, F., 433.Tillett, J.G., 184.Tilney-Bassett, J. F., 117,Timell, T. E., 351, 352.Timmons, R. J., 201.Timnick, A., 128.Ting, S. F., 428.Tio, C. O., 339.Tipson, R. S., 335.Tiptsova, V. G., 416.Tirouflet, J., 445.Titchener, E. B., 357,358.Titus, E., 333.Tlumac, F. N., 94.Tobe, M. L., 105, 130.Tobey, S. W., 181.Tobias, I., 189.Tochtermann, W., 265.Toda, F., 276.Todd, A. (Sir), 237, 261,275, 311.Todd, J. W., 443.Toepffer, H., 345.Tokoroyama, T., 260.Toland, W. G., 203, 206.Tolgyesi, W. S., 85, 209.Tolk, A., 438.Tolman, L. F., 450.TomBsek: V., 304, 320.Tomasi, J., 23.Tomasid, V., 192, 221.Tomita, K., 467, 477.Tomkinson, J. C., 104.Tomlinson, C., 426.Tomlinson, H.M., 426.Topol, L. E., 135.Toptygina, G. M., 123.Torgov, I. V., 332.Toromanoff, E., 323.Torto, F. G., 352.Toscano, V. G., 204.T6th, M., 348.Touma, A., 169.Tomes, C. H., 151.Townley, E., 209, 326.Townsend, J., 152, 443.Tope, K. J., 179, 196.Tracy, J. W., 126, 469.Tramontini, M., 192.Trams, E. G., 362.Trapasso, L. E., 202.Traub, J., 17.Traub, P., 379.Trautschold, I., 313.Treanor, C. E., 48.Trefonas, L. M., 477.Treiber, A., 117.Treibs, A., 264.Treibs, W., 160, 167, 202.Treichel,P.M., 69, 111, 112,114, 117, 119, 237.Treichel, R. B., 118.Trelease, S. F., 301.365.118, 237.Tr6millon, R., 421, 423.Trenner, N. R., 68, 322.Tresselt, L. W., 119.Trifan, D. S., 157.Triffett, A. C. K., 214.Trigg, W.W., 413.Trimble, R. F., 166.Trippett, S., 203,210.Trischmann, H., 172.Tristram, G. R., 373.Tromans, F. R., 98, 462.Trompler, J., 414.Tronev, V. G., 91.Trotman-Dickenson, A. F.,Trotter, J., 144, 234, 473,Trueblood, K. N., 473, 476.Trumbell, E. R., 177.Truscheit, E., 216.Truter, M. R., 119, 134,464, 465.Trzebiatowski, W., 122.Tsang, F., 97.Tschesche, R., 333, 334.Tschudi, C. S., 25.Tsoucaris, G., 476.Tsuboi, M., 36.Tsubomura, H., 102.Tsuda, K., 286, 297, 324.Tsuda, Y., 296.Tsugita, A., 319.Tsuji, J., 244.Tsukamoto, A., 200, 261.Tsuno, Y., 158.Tsutsui, M., 115, 223.Tsjrganova, M. F., 432.Tszh Yun’-Syan, 417.Turk, G., 102.Tufte, T., 463.Tuite, R. J., 61.Tumanova, T. A., 426.Tuppy, H., 304, 317.Turco, A., 129, 130.Turley, R.H., jun., 221.Turnbull, E. R., 215.Turner, D. W., 71.Turner, J. C., 342.Turner, J. J., 57.Turner, R. B., 255.Turner, W. B., 214, 273.Turrian, H., 313.Turvey, J. R., 341, 342,350, 351.Tutundiic, P. S., 424.Tyou, P., 410.Tyrrell, A. C., 449.Tyrrell, H. J. V., 426.Tyson, I. R., 373.Tzschach, A., 98.165, 178.474, 475.Ubbelohde, A. R., 31, 32,Udal’tsova, N. I., 421.Ude, G., 241.33.Udo, Y., 228.Udovenko, V. V., 91.Ueda, I., 474.Ueda, J., 70.Ueda, K., 253, 390.Ueyanagi, J., 301.Ueyo, S., 294.Ugi, I., 181, 201, 275, 310.Uglova, E. V., 168.Uhle, F. C., 296.Uhlig, H., 319.Ulick, S., 334.Ullman, E. F., 238.Ulm, K., 115.Ulmer, H., 96.Ulrich, B., 396.Ulrich, H., 220.Ulsperger, E., 341.Uma, M., 229.Umanskii, M.M., 454.Umapathi, P., 411.Umbreit, W. W., 385.Underhill, A. E., 105.Underkofler, W. L., 441.Underwood, A. L., 420,Underwood, E. E., 420.Undheim, B., 15.Undheim, K., 302.Unrau, A. RI., 352.Urech, J., 331.Urry, G., 90.Utianskaia, E. Z., 66.Utting, K., 300.Utvary, K., 90.Uyeo, S., 296.438.Vagelos, P. L., 366.Vagelos, P. R., 218.Vagelos, R., 364.Vainshtein, B. K., 455, 456,Vainshtein, F. M., 163.Valach, R., 432.Valenta, Z., 297.Valenti, V., 120, 127.Vallarino, L., 232.Valls, J., 323.Valueva, Z. P., 108.Van Adrichem, M. E.,van Ammers, M., 167.van Atta, R. E., 422.Van Baalen, J., 353.van Bekkum, H., 180.Van Daalen, J. J., 212.van de Castle, J.F., 203.van den Berg, J. M., 469.VandenHeuvel, W. J. A.,van der Elsken, J., 44.Vanderhaeghe, H. , 3 1 1.Vanderkam, R. K., 441.Van der Walls, H. W.,459.321.322, 335.153INDEX OF AUTHORS’ NAMES 515VanGEek, J., 304.Van Meter, W. P., 100.van Mews, N., 428.Vannerberg, N.-G., 129,van Niekerk, J. N., 473.van Norman, J. D., 427.Van Overstraeten, A., 266.van Slyke, D. D., 378.Van Tamelen, E. E., 95,201, 278, 290, 299, 300.Van Thiel, M., 43.van Vucht, J. H. N., 460.van Vunakis, H., 320.van Woerden, H. F., 184.Vasil’ev, R. F., 438.Vasina, N. T., 411.Vaska, L., 120.Vasudeva Murthy, A. R.,Vatakencherry, P. A., 251.Vaughan, A., 47.Vaughan, J., 162.Vaughan, P., 455.Vaughan, W. G., 64.Veber, D. F., 233.VeEefa, M., 402, 429.Veda, K., 208.Vedel, J., 423.Veenland, J.U., 206.Veibel, S., 399.Veis, A., 369.Velasco, M., 334.Veldman, H., 394.Veleker, T. J., 433.Velichko, F. K., 274.Vellturo, A. F., 215.Velluz, L., 189, 322, 332.Velten, R. J., 405.Venanzi, L. M., 131, 132,Vendley, R., 212.Venet, A. M., 372.Venkataraman, S., 371.Venkatesan, K., 197.Venkateswarlu, P., 55.Venkateswarlu, V., 41 1.Verbeck, A. H., 441.Verbersik, V., 440.Verbrugge, C., 199, 216.Vercellotti, J. R., 352.Verdier, E. T., 441.Verkade, P. E., 180.Verma, J., 134.Verma, M. R., 398,407,415.Verengo, M. J., 290, 681.Vernon,C.A., 163,176, 183,Vernon, F., 440.Vernon, J. M., 264.Verz&r, F., 369.Verzele, M., 252.Vesely, V., 415.Vesterager, E., 300.Vestrin, R., 394.Vetter, G., 429.462, 466.417.465.337.Vetter, H.-J., 96, 98.Vetter, W., 304.Vickers, C., 432.Vickery, B., 224.Vickery, R.C., 121.Viehe, H. G., 266.Vielstich, W., 441.Viennet, R., 322.Vierling, R. A., 240.Vig, 0. P., 242.Viktorova, E. A., 207.Vilim, O., 437.Vilkas, M., 222.Vill, J. J., 204, 215.Villotti, R., 195, 334.Vinard, D. R., 75.Vincent, E. A., 447.Vincow, G., 152.Vingiello, G. A., 208.Vinogradova, L. P., 242.Vioque, E., 218.Vischer, E., 331.Viscontini, M., 280.Viswanath, G., 234.Viswanatha, T., 303, 320.Viswanathan, K. S., 468.Viswanathan, N., 256.Vitali, R., 327.Vithayathil, P. J., 320.Vittimberga, B., 229.Vl&Eil, F., 404.Vlamis, J., 436.VlEek, A. A., 105, 129, 201.Vodar, B., 39.Vogel, J., 390, 443.Vofsi, D., 220.Vogel, E., 242, 243.Vogel, M., 67.Vogeler, K., 307.Vogler, K., 311, 313.Volger, H. C., 168.Volke, J., 270.Volkov, V.L., 108.Vollbracht, L., 159.Vollmar, A., 306.Vol’pin, M. E., 147, 231.Volpp, G., 331.von Bonin, W., 215.von der Leith, W., 98.von der Plas, H. C., 167.von Euler, H., 394.von Hippel, P. H., 369, 376.von Robe, D., 115.von Kutepow, N., 216.von Lagenthal, W., 289.von Philipsborn, W., 293,von Planta, C., 217.von Saltza, M. H., 342.von Stackelberg, M., 440.von Sturm, F., 445.von Winbush, S., 130.Vo-Quang, L., 221.Vorbrueggen, H., 297.Vorontsova, L. G., 473.Vos, A., 269, 462, 476.294, 478.VrkoE, J., 251.Vydra, F., 425.Wacker, H., 280.Waddington, T.C., 85, 101.Waddington-Feather, S.,Wadsley, A. D., 123.Wadsworth, N. J., 422.Wadsworth, W. J., jun.,Waegell, B., 194.Wlinninen, E., 415.Wager, H. G., 400.Wagner, A., 219.Wagner, A. F., 217.Wagner, E. B., 425.Wagner, W., 418.Wagner-Jauregg, T., 267.Wailes, P. C., 214.Wajda, S., 128.Wakabayashi, N., 253.Wakil, S. J., 218, 353, 354,357, 358, 360, 361.Walba, H., 166.Walborsky, H. M., 136,174,192, 193, 208, 238.Waldron, J. D., 220.Waldschmidt, M., 280.Walia, J. S., 193, 245.Walker, A,, 80.Walker, D. E., 445.Walker, D. M., 203.Walker, J., 300.Walker, J. E., 428.Walker, S., 41.Wall, L. A., 224.Wall, R. A., 335, 336.Wallace, J. W., 75.Wallace, W. J., 106.Wallenfels, K. W., 237.Wallen, P.302.Waller, J.-P., 315, 316.Walling, C., 209, 222.Wallmann, J. C., 460.Wallwork, S. C., 463, 473.Walmsley, S . H., 146.Walsh, K. A., 320.Walsh, P., 19.Walter, T. A., 265.Walters, A. E., 277.Walton, G. N., 79.Wampler, D. L., 465.Wampler, D. S., 110.Wang, F. E., 82, 461,Wang, M.-J., 408.Wannagat, U., 89, 90.Warawa, E. J., 189, 247.Ward, A. G., 369.Ward, E. R., 234.Ward, H. R., 243, 244.Ward, P. F. V., 222.Ward, R., 127.Ward, H. L., 271.326.204, 215.472516 INDEX OF AUTHORS’ NAMESWardlaw, W., 126.Warhurst, E., 36.Wariyar, N. S., 223.Warner, D. T., 305.Warnhoff, E. W., 290, 296.Warren, B. E., 459.Warren, C. K., 217.Warren, F. L., 284, 299.Warshaw, J. B., 354.Wartenpfuhl, F., 126.Wartik, T., 85.Warwicker, E.A., 410.Warwicker, J. O., 476.Waser, J., 98, 477.Wmielewski, C., 306.Wassermann, A., 240.Wassermann, E., 191.Wasserman, H. H., 70, 277,Wasson, G. W., 361.Wasyliw, N., 219.Watanabe, H., 66, 134,345,Waterbury, G. R., 452.Waterman, H., 134.Waters, J. A., 161, 297.Waters, W. A., 165.Watson, C. J., 68, 284.Watson, D. G., 477.Watson, E. J., 185.Watson, H. C., 317.Watson, H. R., 118, 124.Watson, K. J., 474.Watson, R. E., 12, 13, 21,22, 455.Watterson, K. F., 69.Watts, W. E., 117, 237.Waugh, J. S., 56, 59, 60,67, 78.Wawzonek, S., 439.Way, J. K., 190.Wayne, R., 209, 326.Wayne-Meinke, W., 446.Weale, K. E., 178.Webber, G. M., 201.Webber, J. M., 352.Weber, E., 319.Webster, B., 266.Webster, D.E., 69.Webster, M. E., 313.Webster, 0. W., 211, 223.Webster, R. K., 447, 449,Weddige, H., 307.Weedon, B. C. L., 68, 216,Wehner, J. F., 139.Wehrli, H., 331.Wei, Y.-K., 107.Weidenhagen, R., 338.Weidmann, H., 342.Weigel, H., 336, 337, 339,Weigel, H. J., 411.Weigmann, H.-D., 215.Weiland, J. H. S., 212.312.467, 476.450.217.345.Weil-Malherbe, H., 394.Weiner, M. A., 59, 208.Weingarten, H., 165.Weininger, J. L., 88.Weinstock, B., 128, 130.Weir, C. E., 438.Weise, E., 469.Weisner, K., 297.Weiss, A., 24, 139.Weiss, A. W., 12, 15, 19.Weiss, C., 160.Weiss, E., 113, 333, 369.Weiss, J., 463.Weiss, M. J., 324.Weiss, U., 188.Weissbach, H., 278.Weissbach, O., 278.Weissmann, C., 292.Weissman, S.I., 149, 152.Weitkamp, H., 390.Welch, V. A., 183.Weliky, N. E., 77.Wellman, W. E., 49.Welsh, F. E., 438.Welvart, Z., 231.Wender, I., 201.Wendler, N. L., 68, 322,Wenger, P. E., 443.Wenkert, E., 254, 255, 256,Wentorf, R. H., 85.Wepster, B. M., 180.Werle, E., 313.Werner, H., 114, 236.Werner, R. P. M., 108, 109,Wessely, L., 353.West, B. O., 103.West, C. A., 300.West, P. W., 404.West, R., 41, 80, 89, 171,West, T. S., 96, 248, 415,West, W., 35.Westenbrink, H. G., 394.Westheimer, F. H., 154,Westlake, D. W. S., 350.Westland, A. D., 104.Westland, L., 104.Westrum, E. F., 94.Wettstein, A., 327,330,334.Weygand, F., 265, 280,Whaley, H. A., 300.Whalley, E., 182.Whalley, W. B., 323.Wharton, P. S., 70, 201.Wheatley, P.J., 80, 235,465, 470, 474, 475, 477.Wheeler, T. S., 68, 283.mhelan, W. J., 348, 350,Wheland, G. W., 147.326, 328.286.110, 118.208.436.183.307, 336.351.Whetsel, K. B., 36.Whiffen, D. H., 81, 87, 190.Whipple, E. B., 41, 70.Whistler, R. L., 345, 349.Whitaker, R. D., 101.Whitear, B., 231, 240, 274.White, C. G., 450.White, D. C., 431.White, D. G., 92.White, E. A. D., 79.White, E. H., 41, 281.White, F. H., 320.White, J. D., 278.White, H. S., 159.White, R. F. M., 62, 97,White, T., 237.White, W. N., 159.Whitehead, J. K., 304.Whitehead, R., 20.Whitham, B. T., 410.Whitham, G. H., 174, 202,241, 243, 250, 324.Whiting, D. A., 283.Whiting, M. C., 193, 215.Whitman, D. R., 56.Whitnack, G.C., 443, 444.Whittaker, D., 185.Whittern, R. N., 398.Whittig, L. D., 132.Whittle, E., 43.Wiberg, E., 95.Wiberg, K. B., 107, 203,Wick, A. K., 225, 342.Wick, A. N., 354.Wickens, J. C., 219.Wickliffe, R. A., 223.Widom, B., 33.Wiebenga, E. H., 101.Wiegers, G. A., 462.Wiehle, D., 263.Wieland, O., 353.Wieland, P., 327, 330.Wieland, T., 293, 307, 312.Wiesboeck, R., 170.Wiewiorowski, M., 286.Wildman, W. C., 285, 294,295, 296, 299.Wilen, S. H., 231.Wiles, R. A,, 155.Wiley, R. H., 274.Wilhelm, M., 279.Wilhelmi, K., 102, 126.Wilkins, C. J., 90, 93.Wilkinson, G., 38, 69, 111,112, 113, 114, 11.5, 117,120, 127, 128.240.239, 245.Nilkinson, G. R., 44.Nilkinson, J. V., 432.Nilkinson, M. K., 126, 456,Nilkinson, P. A., 326.vVillard, H. H., 398.Willard, J. E., 53.Wille, F., 212.469INDEX OF AUTHORS' NAMES 517Willi, A. V., 154, 156, 160.Williams, A. E., 450.Williams, A. I., 447.Williams, A. R., 264.Williams, B. J., 234, 240.Williams, D., 432.William, D. E., 436.Williams, D. I., 442.Williams, G. A., 150.Williams, G. H., 165, 166,Williams, G. J., 453.Williams, J., 82.Williams, J. M., 342.Williams, L. P., 171.Williams, M. W., 307.Williams, N. R., 338.Williams, P. H., 202.Williams, R. E., 66.Williams, R. J. P., 104.Williams, R. L., 37, 38, 41,Williams, R. O., 233, 246.Williams, T. P., 341, 342.Williams, W. J., 412.Williamson, K. L., 324.Willis, H. A., 410.Willis, J. B., 438.Willner, D., 193, 245.Wilmarth, W. K., 106, 129,Wilmhurst, J. L., 149.Wilson, A. L., 399.Wilson, C. L., 433.Wilson, C. O., 451.Wilson, D. V., 272, 273.Wilson, E. B., 17, 186, 140.Wilson, G. R., 88.Wilson, H. J., 417.Wilson, H. N., 426.Wilson, I. R., 184, 443.Wilson, J. D., 445, 449.Wilson, T. L., 218.Wilt, M. H., 205.Winberg, H. E., 225.Windsor, M., 30, 50.Winefordner, J. D., 426,Winestock, G., 315.Winitz, M., 300, 307.Winkhays, G., 69.Winkler, W., 289.Winn, A. V., 248.Winstein, S., 173, 174, 176,Winter, E., 108.Winterfeldt, E., 286.Winterstein, A., 216, 217.Wintersteiner, O., 342.Wirz, R., 219.Wise, E. N., 423.Wish, L., 448.Witkop, B., 278, 301, 302,Witmer, W. B., 101.Witnauer, L. P., 368.231.82.154.433.180, 246.303.R"Witteman, W. J., 33, 50.Witter, A., 304.Wittig, G., 215, 265.Wittmann-Liebold, B., 317.Wohrle, H., 469.Woggon, H., 440.Wojcicki, A., 108, 109, 131.Wojciechowski, W., 128.Wojtkowiak, B., 36.Wolf, K., 374.Wolf, L., 466.Wolf, v., 212.Wolf, w., 210.Wolfe, J. B., 354.Wolfenden, D. R., 182, 183.Wolff, I. A., 218.Wolfram, R., 382.Wolfrom, M. L., 340, 341,Wollan, E. O., 456.Wollish, E. G , 408.Wollman, K., 108.Wolman, Y., 308.Wolovsky, R., 205, 215,Womack, C. M., 22, 456.Woo, G. L., 182.Woo, P. W. K., 339.Wood, D. F., 445.Wood, G. C., 370.Wood, H. C. S., 281.Wood, J. H., 22, 431.Wood, J. S., 131, 468.Wood, T. M., 68.Wood, W. A., 385.Woodmansee, W. E., 50.Woods, L. L., 272.Woodward, R. B., 188, 189,212, 269, 297, 308, 322.Woolf, A. A., 127.Woolfson, M. M., 454, 473.Woolmington, K. G., 400,Woolner, M. E., 315.Wooster, W. A., 453.Worden, L. R., 255.Worsham, J. E., 455.Worsley, B. H., 21.Wotiz, H. H., 322.Wotiz, J. H., 210, 212.Wright, A., 349.Wright, D., 259.Wright, G., 168.Wright, G. A., 183.Wright, G. J., 162.Wright, J. M., 424.Wright, L. D., 321.Wright, S. E., 333.Wrigley, A. M., 270.Wulff, G., 333.Wunderlich, J. A., 454,Wurster, W. H., 48.Wyatt, P. A. H., 153.Wynne-Jones, W. F. K.,352.219, 234.410.461.165.Wystrach, V. P., 222.Wyszomirski, E., 96.Xavier, J., 116.Yagi, K., 345.Yajima, H., 306, 315, 316.Yakel, H. L., 457, 469.Yakel, H. L., jun., 126.Yakovleva, T. V., 36, 41.Yamada, K., 273.Yamada, S., 302.Yamaguchi, I., 74.Yamaguchi, T., 342.Yamamoto, O., 430.Yamamoto, Y., 274.Yamano, T., 333.Yamanouchi, Y., 41.Yamauchi, F., 345.Yamazaki, H., 211.Yamazaki, M., 26, 153, 167.Yamozaki, K., 49.Yanaihara, N., 316.Yanari, S., 305.Yang, N. C., 206.Yanofsky, C., 383, 384, 385,386, 387, 388.Yardley, J. P., 258.Yardley, J. T., 413.Yasnikov, A. A., 163.Yatco-Manzo, E., 395.Yates, D. J. C., 44, 45.Yates, J. T., 45.Yates, K. O., 294.Yates, P., 203, 246, 278.Yavit, J., 390.Yeh, Y. L., 310.Yeowell,D.A.,293,293,478.Yoneda, Y., 460.Yonemitsu, O., 291.Yonezawa, T., 147,148,158.Yonezawa, Y., 66.York, J. L., 182.Yorka, K. V., 207.Yoshi, S., 381.Yoshimine, M., 24, 139.Yoshino, Y., 107.Yoshikawa, K., 400, 430.Yoshizumi,H., 138,141,148.Yosioka, I., 253.Youden, W. J., 399.Young, A. E., 136, 193,Young, D. V., 197.Young, G. T., 306, 307.Young, J., 319.Young, J. A., 94.Young, J. E., 29.Young, J. H., 406.Young, N. C., 229.Young, R. J., 180.Young, S. T., 144.Young, W. G., 216.Yount, R. G., 395.208, 238518 INDEX OF AUTHORS’ NAMESYoussef, A. A., 174.Yu, K. C., 91.Yuan, C., 218.Yuan, E., 325.Yuan-Lang Chow, 254.Yudis, M. D., 328.Yuen, G. Y., 338.Yukawa, Y., 158.Yule, K. C., 343.Zabin, I., 354.Zacharias, D. E., 291.Zacharias, J., 372.Zachariasen, W. H., 121,Zadrazil, S., 261.Zaffarano, D. J., 446.Zahn, H., 220, 302.Zahn, U., 118.Zahner, H., 348.Zahradnik, R., 158,266,371.Zaits, K. A., 184.Zakharov, M. S., 442.Zakharov, V. A., 421.Zalkin, A., 465.Zalkow, L. H., 252.Zalkow, V. B., 248.460, 470.Zambonelli, L., 476.Zander, N., 144.Zaoral, M., 300, 305, 306.ZLttka, V., 404.Zaugg, H. E., 172.Zhvada, J., 243.Zav’yalov, S. I., 242.Zderic, J. A., 197.Zebe, E. C., 365.Zecher, W., 271.Zeiss, H., 115, 223.Zeitler, G., 109.Zeitz, M. E. A., 335.Zelle, A,, 433.Zener, C., 32.Zenhaiisern, A., 75.Zerner, B., 180, 184.Zervas, L., 306, 307.Zevin, L. S., 454.Zhdanov, G. S., 473.Zhigalkina, T. S., 434.Ziegler, M., 409.Ziffer, H., 188, 322.Zilliken, F., 342.Zinunerman, G. I., 163.Zimmerman, H. E., 171.Zimmerman, H. K., jun.,342.Zimmermann, F., 240.Zimmermann, H., 166.Zingales, F., 232.Zingaro, R. A., 101.Zinner, H., 343.Zipper, H., 374.Zissis, E., 340.Zittel, H. E., 423.Zixlsperger, H., 109.Zlatovich, S. A., 47.Zobel, H., 218.Zonnchen, W., 305.Zollinger, H., 75, 165, 219,Zoltewicz, J. A., 275.Zorbach, W. W., 339.Zuber, H., 302, 313.Zuckerkandl, E., 317.Ziircher, R. F., 68, 322.Zuman, P., 184.Zvonkova, Z. V., 472, 473.Zwanzig, R., 33, 51.Zweifel, G., 198, 199, 213,216, 242.Zweig, A., 171.Zwickel, A., 86, 106.Zyka, J., 421, 422.Zylber, J., 258.233, 348

ISSN:0365-6217    

DOI:10.1039/AR9615800481

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

INDEX OF SUBJECTS(dtmn. = determination)fibsolute configuration, 192.Acetylene, molecular-energy transfer in,Acetylene complexes, 115.Acetylenes, 21 0.trimerimtion of, 222.Acetylenic compounds, naturally occur-Acidity functions, 153.Acids, fatty, biosynthesis of, 353.Acridine, 3-hydroxy-9-phenyl-, forms of,Actinides, the, 121.Actinidine, absolute stereochemistry of,,4damantane, formation of, 246.Addition compounds, crystal structure of,Adenine, synthesis of, 279.Agaratine, structure of, 301.Ajmalicine, total synthesis of, 290.Alangine-A, erroneous structure of, 287.Alcohols, dtmn. of, 426.hydrogen bonds in, 74.Aldehydes, aliphatic, preparation of, 200.test for, in presence of ketones, 403.Aldoses, distinction of, from ketoses, 403.reactions of, at position 1, 340.Alicyclic compounds, 237.Aliphatic compounds, 210Alkaloids, biogenesis of, 285.Acetone a d , ” formulation of, 278.32.ring, 213.via malonyl-CoA, 356.281.287.463.curare, 292.isoquinoline, 289.lupin, configurations of, 286.steroidal, 296.terpene, 297.Alkoxyl groups, dtmn.of, 418, 426.Alkylation, 207Allenes, 214--Ally1 derivative: use of the term, 236.Alhrnmic acid, biosynthesis of, 273.Aluminium, dtmn. of, 413, 416.separation of, 404.Aluminium alkyls, dtmn. of, 417.dialkylamino-derivatives of, 86.hydride, complexes of, 85.Ambrosin, structure of, 259.Americium, crystal structure of, 460.h i d e s , protonation in, 75.Amination, 230.Amines, dtmn. of, 405, 418.Amino-acids, 300.N-methyl-, protonation in, 75.in collagens, 372.sulphur-containing, 301.a-Amino-acids, dtmn.of, 443.2-Aminoethanol phosphate, crystal struc-Amino-sugars, 342.Ammonium fluoride, forms of, 94.a-Amyrin acetate, interconversion of, withAnagyrine, absolute co&guration of, 286.Analytical chemistry, 397.Angiotensin (hypertensin), structure of,Angustifoline, identity of, with jamacien-Aniline, 4-nitro-, crystal structure of, 473.Anions, basicity of, 171.Anthracene, 9-bromo-10-chloro- and -10-methyl-, crystal structure of, 474.Antibiotics, 310.Antimony, dtmn. of, in presence of arsenic,ture of, 472.isoursenyl acetate, 258.313.sine, 286.nucleophilicity of, 17 1.412.in refined lead, 442.L-Arabinose, inversion of, 337.13-L-Arabinose, angles in, 335.Arborinine, structure of, 289.Aristolone, structure of, 253.Armoline, structure of, 290.Aromatic compounds, 222.Aromatic systems, complexes with, 116.nuclear magnetic resonance measure-Aromaticity and reactivity, 146.Arsenic, dtmn.of, in presence of anti-Arsenic acid, esters of, 99.Arsenobenzene, crystal structure of, 477.Arsonium ion, identification of, 98.ments in, 157.mony, 421.structure of, 98.Ascaridole, reduction of, 248.Ascorbic acid, dtmn. of, 424.Asiatic acid, identity of, with dammarolicAsparagine monohydrate, crystal struc-Astatine, preparation of, 102.Asymmetric induction, 192.Atoms, wave-mechanical calculations in, 7.Aureothin, structure of, 273.Azido-alcohol, a stable, 240.Aziridines, 261.Azodicarboxamide, crystal structure of,Azulene, protonation of, 76.acid, 258.ture of, 479.473.2-phenyl-, crystal structure of, 475.Balchanolide, structure of, 251.Barbituric acid dihydrate, crystal struc-ture of, 476.51520 INDEX OF SUBJECTSBarium, dtmn.of, 413.Barley, new constituents of, 277.Bee substances, 2 17.Benzaldehyde p-nitrophenylhydrazone aspH indicator, 400.Benzene, reaction of, with maleic an-hydride, 223.Benzoic acid, p-chloro-, reaction of, withethanolic potassium cyanide, 230.p-Benzoquinone, “ trimer ” of, 282.Benzothiazoles, formation of, 281.Benzothiazoline, 3-methyl-2-thio-, crystalBenzothiazolines, formation of, 281.3-Benzoxepin, preparation of, 276.Beryllium, dtmn.of, 407, 411.Beryllium atom, the, 20.Biaryls, preparation of, 210.Bicyclo [4,6,0]dodec-l(6)-ene,formationof,Bicyclovetivenol, structure of, 253.Biformene, formation of, 255.3,3‘-Bi-isoxazolyl, formation of, 268.1,l’-Binaphthyl, optically active, 190.Biological chemistry, 353.Biosynthesis of fatty acids, 353.Biphenyl, crystal structure of, 473.test for, 401.structure of, 477.nitrate, basic, 80.243.4,4’-dihydroxy-, crystal structure of,4,4‘-dinitro-, crystal structure of, 473.Biphenylene, 233.Birch reductions, improvements in, 201.Bishomogramicidin S, synthesis of, 31 1.Bismuth, dtmn. of, 417, 421.Alkylbismuth hydrides, 99Bitetrazolyl, true structure of, 269.3,3’-Bithienyl, optically active, derivativeBitter principles, 259.Blood proteins, 317.Boron, dtmn.of, in organic compounds,Boron hydrides, crystal structure of, 460.473.of, 190.432.test for, in silicate ores, 402.nitride, crystalline forms of, 85.trifluoride, molecular-energy transfer in,Boron-containing acetylenic compounds,31.reactions of, 84.213.Boranes, alkyl-, preparation of, 82.aminodiaryl-, preparation of, 83.arsinodiaryl-, preparation of, 83.phosphinodiaryl-, preparation of, 82.Borate complexes with carbohydrates,Borazole, BBB-trichloro-, preparationBorazoles, reactions of, 83.Borides, crystal structure of, 461.Borohydrides, alkali, use of, 200.Decaborane, methylation of, 82.Decaboron hexadecahydride, 82.337.of, 84.reactions of, 82.Diborane, preparation of, 81.Diboron tetrachloride, preparation andreactions of, 85.Dimethylaminoborine trimer, crystalstructure of, 477.Hydroboronation, 198.Sodium borohydride, preparation of, 81.Sodium peroxoborate, structure of, 85.Tetraborane, reactions of, 81.Tetraborane “ diammoniate,” nature of,Bradykinin, amino-acid sequence in, 313.Brazilensis, structure of, 252.Bromine, nitrates of, 101.2-Bromobutane, optically active, 191.Bufotenin, dehydro-, fission of, 278.Buphanamine, 2 9 4.Butane, 2-bromo-, optically active, 191.Butan-2-01, asymmetric synthesis of,Butenolides, formation of, 265.Butyl alcohols, spin-lattice relaxationt-Butyl peresters, use of, 202.t-Butylbenzenes, properties of, 223.But-2-yne, hexafluoro-, reactions of, 213.tetrakisdimethylamino -, 83.reactions of, 81.81.identity of, with kallidin I, 313.199.time in, 78.Cadmium(1) species, existence of, 135.Caesium chloride, titration of, 420.Cafestol, configuration of, 257.Calacone, structure of, 251.Calcium, dtmn.of, in ferromanganeseslags, 415.in water, 425.test for, 401.( + ) -Camphane, 1 O-bromo-2-chloro-2-nitroso-, crystal structure of, 479.(&)-Camphor, resolution of, 249.Carbanion rearrangements, 171.Carbenes, 178.Carbohydrates, 335.cyclic derivatives of, 339.deoxy-, 339.esters of, 341.oxidation of, 337.separation of, 335, 344.sulphur-containing derivatives of, 343.(see also Saccharides.)Carbon, dtmn. of, in organic compounds,Carbides, crystal structure of, 462.Carbon dioxide, dtmn.of, 414.Carbon monoxide, molecular-energyreduction by, in aqueous solution,429.molecular-energy transfer in, 30.transfer in, 29.87.Carbonic acid-ether complex, 87.Carbonium ions, 173.Carbonyl and related reactions, 179.Carbonyl compounds, formation of, 205.Carbonyls, 108INDEX OF SUBJECTS 521Carboxylic acids, crystal structure of, 471.uses of, 206.Carotenoids, 216.Carotol, structure of, 252.Catechol, test for, 403.Catharanthine, structure of, 292.Ceanothic acid, stereochemistry of, 259.Cedrene, structure of, 254.( + )-Cedrol, synthesis of, 251.Cedrolic acid, structure of, 254.8-Cellobiose, crystal structure of, 480.Cellulose, 347.Cephalosporin C, crystal structure of,Chalcose, structure of, 339.Chelatometric titrations, 415.Chemical shifts, 150.dyes which react with, 347.478.intermolecular effects, 7 1.intramolecular effects, 63.8-Chitin, crystal structure of, 479.Chloral, cyclic tetramer of, formulation of,Chloranil, crystal structure of, 474.Chloride, dtmn.of small quantities of,Chlorine, molecular-energy transfer in, 30.o-Chlorobenzoic acid, crystal structure of,471.2 - Chloro -p -benzo quinone 4 - oxime acetate,crystal structure of, 474.Chlorocarbene, preparation of, 264.Chloropicrin, test for, 403.Chloropropenium ions, 231.Cholanthrene, 20-methyl-, crystal struc-Cholesterol, dtmn. of, 437.Chromatography, column, 406.276.428.ture of, 474.gas, 409.paper, 406.thin-layer, 408.monoxide, 125.Chromium carbide, 125.Chromium(I1) chloride, 126.crystal structure of, 468.Chromyl azide, 126.Chromium(II1) complexes with malon-aldehyde and formylacetone, 105.Chromic acid, use of, in organic oxida-tion, 203.Dibenzenechromium, 157.Iodopentacarbonylchromium, 1 09.Chromones, 5,6,7,8 -tetrahydro -, forma tionChronopotentiometry, 419, 427.Clerodin, structure of, 259.Cobalt, dtmn.of, 425.separation of, 407.test for, 402.Cobalt complexes, 129.Coccinine, structure of, 295.Colimycin, structure of, 31 1.Collagenases, 374.Collagens, 367.Communic acid, structure of, 256.Conessine, synthesis of, 296, 329.of, 283.Conformational analysis, 193.Conjugated systems, molecular-orbital cal-Convallamarogenin, structure of, 333.Co-ordination compounds, crystal struc-Copalic acid, structure of, 256.Copper, 132.culations on, 143.ture of, 465.dtmn.of, 407.separation of, 405.Copper(I1) formate, crystal struct,ure of,471.royal-blue, structure of, 134.Copper@) hydroxide, crystal structureof, 470.Acetylacetonat,o -0-hydroxyanilatocop-per@) complex, structure of, 133.Bisbenzeneazo-2-naphtholcopper, struc-ture of, 467.Diazoaminobenzenecopper, crystalstructure of, 465.structure of, 133.Correlation energy, 14.definition of, 10.Costunolide, dihydro- 12-methoxy-, struc-ture of, 251.p-Cresol, test for, 402.Crinamidine, structure of, 294.Cryptopimaric acid, identity of, with san-daracopimaric acid, 256.structure of, 256.Crystallography, 453.(&)-Cuparene, structure of, 251.Cyanamide, crystal structure of, 472.Cyanide, dtmn.of, 421.molecular-energy transfer in, 29.Cyanide ions, crystal structure of, 462.Sodium cyanide, reactions of, withCyc1(3,2,2)azine, crystal structure of, 477.1,4-dibromo-, crystal structure of, 477.Cyclic polyenes, 232.Cycloarten- 23-ene- 3/3,25-diol, structure of,Cyclobutane ring, conformation of, 196.Cyclobutene, 3, 4-dimethylene-, 240.Cyclobutenones, formation of, 212.Cyclohexadienone, 2-methylene- (o- quinoneCyclohexane, hexaethylidene-, formationboranes, 82.259.methide), 228.of, 242.hexamethylene-. See Radialene.Cyclohexane derivatives, conformation of,Cyclohexanone, 4-chloro-, reduction of,Cyclo-octatetraene, reaction with potas-Cyclopentadienyl ions, 231.Cyclopentane, l,l,Z-trichloro-, conforma-tion of, 196.Cyclopropanes, 237.Cyclopropene derivatives, 239.Cysteine, use of, as masking agent, 41 5.Cytochrome c, amino-acid sequence in,194.241.sium, 80.317522 INDEX OF SUBJECTSDammarolic acid, identity of, with asiaticDaniellic acid, structure of, 256.Daphnandrine, structure of, 290.Daphnoline, structure of, 290.Daucol, structure of, 252.Dauritigenol, structure of, 257.Dehydroabietic acid, reduction of, 255.Dehydrococcinine, structure of, 295.Delcosine, structure of, 298.Delsoline, structure of, 298.Dendropanoxide, structure of, 258.2-Deoxy-p-~-ribose, conformation of, 335.Deoxy-sugars, 339.( + ) - 1,2 -Dianilino- 1,2 -diphenylethane, an-Diazines, 274.meso-l,4-Diaziridin-l’-ylbutane-2,3-diol,Diaziridines, 261.Diazirines, 261.Diazoalkanes, preparation of, 210.Diazocycloalkanes, decomposition of, 242.Diazoethane, homologation of cyclicDiazomethane, preparation of, 266.Diazonium compounds, preparation and1,2 : 7,8-Dibenzocoronene, crystal struc-truns-orj?-Dicyanostilbene, crystal struc-Diels-Alder adducts, bridged, dtmn. ofconfiguration of, 4141,3-Dienes, dtmn.of, 418.Diethynyl ketone, 212.Digacetigenin, structure of, 334.Digalogenin, structure of, 333.Digipurpurogenins-I and -11, structure of,17a-Digitoxigenin, formation of, 332.Dimethylformamide, purification of, 41 7.Dimethylglyoxime, crystal structure of,472.m-Dinitrobenzene, crystal structure of,474.2,4-Dinitrobenzene, 1 -bromo- and 1-chloro-, crystal structure of, 474.Dioscorine, structure of, 298.1,3-Dioxan, cis- and trans-5-acetoxy-2-phenyl-, conformation of, 273.1,3-Dioxans, isomerisation of, 273.1,3-Dioxole, preparation of, 270.2,3-Diphenyltartaric diamide, conversionof, into 2-benzoyl-5-phenylimidazol-4-one, 267.Disaccharides, 344.Distance, interelectronic, 20.Disulphides, aliphatic, unsymmetrical,Dithizonate ion, crystal structure of,Di-p-tolyl disulphide, crystal structure of,Dolichodial, structure of, 248.Dyes which react with cellulose, 347.acid, 258.alytical use of, 403.crystal structure of, 475.ketones by, 242.reactions of, 209.ture of, 475.ture of, 473.334.synthesis of, 221.467.473.Echitamine, structure of, 292.Electrodeposition, 439.Electrolytic potentiometry, differential,Electron-coupled nuclear spin-spin inter-Electron distribution in accurate struc-Electron population analysis, 142.Electron resonance effects, interpretationElectron-spin resonance, 151.Electrophoresis, 408.Elements, crystal structure of, 460.Eliminations, gas-phase, 184.Emmolic acid.See Ceanothic acid.End-point determination, amperometric,419.actions, 57.ture analysis, 455.of, 149.420.chronopotentiometric, 427.conductometric, 41 9.coulometric, 422.high-frequency, 427.instrumental, 418.potentiometric, 424.Enneacarbonyls, true composition of, 109.Epilimonol iodoacetate, crystal structureEremophilone, absolute configuration of,Erythropterin, structure of, 281.Ethane, molecular-energy transfer in, 32.1,2-dichloro-, crystal structure of, 472.E thyl 1 -methyl- 4-phenylpiperidine - 4-car-boxylate, crystal structure of, 476.N-E thyl- 2,2’- dime th ylsulphonylvinylid -eneamine, crystal structure of, 473.Ethylene, molecular-energy transfer in, 32.Ethylenedi(amm0nium sulphate), crystalEucarvone, irradiation of, 242.Europium, dtmn.of, 423, 442.of, 477.252.structure of, 472.Factor S of staphylomycin, structure of,Fatty acids, 217.Ferricyanide, dtmn. of, 425.Ferrocene, rotation of cyclopentadieneFerroelectric crystals, 457.Filipin, structure of, 277.Flame photometry, 434.Flavensomycinic acid, structure of, 240.Flexinine, structure of, 295.Fluorimetry, 435.Fluorobenzenes, formation of, 224.nucleophilic reactions of, 230.Fluorochlorites, 79.Formylacetone complexes of chromium-(111), 165.Fructose, dtmn.of, 422.D-Fructose, alteration of, 336.Fulvalene, perchloro-, crystal structure ofFulvalenes, 234.311.natural, derivatives of, 219.rings in, 77.475INDEX OF SUBJECTS 523Fulvene, dimethyl-, crystal structure of,475.Fulvic acid, structure of, 283.Furans, 265.tetrahydro-, 265.Gadolinium chloride hexahydrate, crystalstructure of, 470.Gafrinin, structure of, 251.Gallium, trivinyl-, preparation of, 87.Garryfoline, absolute stereochemistry of,Gas-phase eliminations, 184.Gelatin, definition of, 369.Gelatine, definition of, 369.Gelsemicine, crystal structure of, 478.General and physical chemistry, 7.Germacrone, structure of, 251.Germanium &fluoride, 9 1.297.Dichlorogermanium phthalocyanine, 92.Germane, preparation of, 91.methoxytrimethyl-, 91.monofluoro-, 91.trimethylchloro-, 91.of, 257.Gibberellic acid, stereochemical structureGlucose, dtmn.of, 422.Glutarimide, a-ethyl-a'-iodo-a-phenyl-,Glycine, dtmn. of, 408.Glycogen, 348.Glycoproteins, 321.Glycosides, 337.Glycylphenylalanylglycine, crystal struc-Gold, separation of, 405.Gravimetric analysis, 41 1.Grayanotoxin I, 11, and 111, structures of,Grignard reagent, an optically active,Grindelic acid, structure of, 256.Guaiol, absolute configuration of, 252.Gums, plant, 352.crystal structure of, 476.ture of, 479.257.238.Haemoglobin, human, chain sequences in,318.Hafnium, 122.Halides, crystal structure of, 468.dtmn.of, 426.Halogenation, 163.Halogens, dtmn. of, in organic compounds,titration of, 414.Helianthrone, optically active, 190.Helium atom, the, 16.Hemicelluloses, 351.Heptalene, 235.Heptalenium fluoroborate, 236.Heptaphenyltropylium, synthesis of, 232.Herbipoline, synthesis of, 280.Heteroaromatic compounds, 166.Heterocyclic compounds, 260.Heteropoly-blue, formation of, 436.431.1,12 : 2,3 : 4,5 : 6,7 : 8,9 : 10,ll-Hexabenzo-Hexahelicene, " inherent '' asymmetry in,Hexan-3-01, asymmetric synthesis of, 199.D L - ~ ~ o - 3 -Hexulose, preparation of, 338.u- and 8-Himalchene, structure of, 253.Himandravine, structure of, 288.Himbacine, structure of, 287.Himbeline, structure of, 288.Himgravine, structure of, 288.Hinesol, structure of, 253.Hinokiic acid, structure of, 253.(&)-Hinokione methyl ether, structure of,Hispidin, structure of, 272.Holeinine, structure of, 292.Homogeneous solution, precipitation from,Hulupones, 259.Hydrates, crystal structure of, 470.Hydration numbers, 76.Hydrazine, analytical use of, 412.Hydrazines, reduction of olefins by, 201.Hydrides, crystal structure of, 460.Hydrogen, dtmn.of, in organic com-molecular-energy transfer in, 29.replacement ofothersubstituents by, 160.Hydrogen bonding, 457.Hydrogen bonds, intermolecular, in alco-Hydrogen-isotope exchange in aromaticHydrogen molecule, the, 24.coronene, crystal structure of, 475.189.254.412.oxidation of, 426.silyl-substituted, 89.pounds, 429.hols and phenols, 74.systems, 159.molecule-ion, the, 22.Hydrogen cyanide tetramer, crystalstructure of, 472.Hydrogen peroxide, use of, in organicoxidation, 202.Hydrogenation, catalytic, 197.Hydroxides, crystal structure of, 470.Hydroxylation by micro-organisms, 335.Hypertensin (angiotensin), structure of,313.Ice I, structure of, 457.Ichthyocol, 367.L-Idothiapyranose, formation of, 344.Imidazole, oligomers of, 266.Indirubin, crystal structure of, 477.Indium, dtmn.of, 421.separation of, 404.Indole, 2,3-diethyl-, autoxidation of, 277.Indoles, 2-aryl-, structure of, 277.preparation of, 278.3-substituted, dimerisation of, 277.Infrared spectra and molecular interac-Inorganic chemistry, 79.tions, 34.complexes, mechanisms of reactions of,structures, 460.106524 INDEX O F SUBJECTSIntermolecular forces and solvent effects,Iodine, molecular complexes of, 102.Iodine ions, positive, 102.34.Iodide, dtmn.of small amounts of,423.Ion exchange, in inorganic analysis, 409.Iron, complexes of, 128.Iron, dtmn. of, 417.traces of, 424.separation of, 405.rr-Benzenecyclopentadieneiron(O), truenature of, 11 5.Butadieneiron tricarbonyl, structure of,112.Cyclo-octatetraenedi-iron hexacarbonyl,structure of, 113.Iron(II), dtmn. of, 414, 417.Isobalchanolide, structure of, 251.Isochiapagenin, structure of, 334.Isogermacrone, structure of, 251.Isoindoline, lY3,4,7-tetramethyl-, prepara-Isopimaric acid, stereochemistry of, 256.Isoquinolines, 279.Isotelekin, structure of, 252.Isoteracacidin, structure of, 283.Isotope effects involving deuterium, 154.tion of, 278.primary, 154.secondary, 155.solvent, 155.with a-amyrin acetate, 258.Isoursenyl acetate, interconversion of,Isoxanthopterin, structure of, 281.Isoxazole, 5-hydroxy-2,3-dimethyl-, 268.Jamaicensine, identity of, with angusti-Jatamansone, absolute configuration of,Jervine, absolute cont?guration of, 297.Julocrotine, structure of, 299.foline, 286.252.Kallidin I, identity of, with bradykinin,Kallidin 11, structure of, 313.Kationic acid, structure of, 259.(- )-Kaurene, stereochemistry of, 256.a-Keto-esters, formation of, 212.Ketoses, distinction of, from aldoses,Ketoximes, nuclear magnetic resonancea-Kojibiose, preparation of, 345.Kojic acid, dtmn.of, 418.Krigenamine, structure of, 299.313.403.in, 74.8-Lactones, synthesis of, 262.8- and 8-Lactones, formation of, 206.Lead, dtmn. of, 411.tetra-acetate, new application of, 330.Triphenyl-lead azide, 94.Leucotylin, structure of, 259.Leucrose, formation of, 345.Liriodenine, structure of, 289.Lithium aluminium hydride, uses of, 85,200.atom, the, 20.methoxide, crystal structure of, 470.Benzyl-lithium, formation of, 208Ethyl-lithium, polymers in vapour of,Tri-n-butylstannyl-lithium, 92.( &):Longifolene, synthesis of, 251.Lucidusculine, structure of, 298.Luvigenin, structure of, 333.Lycofoline, structure of, 298.Lysopine, structure of, 301.79.Maesopsin, formulation of, 282.Magnesium, dtmn.of, in ferromanganeseslags, 415.in pyrolusite, 415.in water, 425.Diethylmagnesium, preparation of, 80.Organomagnesium halides, preparationof, 80.Magnetic structures, 456.Maleic anhydride, reaction of, with ben-Maleimide, polymerisation of, 264.Malonaldehyde complexes of chromium-Malonyl-CoA, function of, in fatty-acidManganese, 1 2 7.dtmn. of, 425.zene, 223.(111), 105.synthesis, 356.in glasses, 442.in pyrolusite, 415.in steels, 427.203.dioxide, use of, in organic oxidations,Dimanganese decacarbonyl, 108.Manganese nitrosyltetracarbonyl, 11 1.Manganate(vI), oxidation of, by hypo-chlorite, 107.D-Mannosides, formation of, 337.Ma,nool, dehydration of, 255.Mass spectrometry, 450.Matricarcin, structure of, 253.Matrix isolation technique, 43.Maytenone, structure of, 258.Mellitic acid, crystal structure of, 472.Mercury, 134.Mercury(II), dtmn.of, 425.oxide, 87.Metagenin, structure of, 333.Metal carbonyl cations, 109.Metal complexes with discrete moleculesor ions, crystal structure of, 466.Metallocenes, 236.Metaphenine, structure of, 289.Methane, molecular-energy transfer in,Methanolates of alkali metals, 80.Methronic acid, mechanism of formationsalts of, reduction of, by carbon mon-31.of, 265INDEX O F SUBJECTS 525Me thylenec yclopropane sys tem, route to,(+ )-l-Methylheptyl nitrite, alcoholysis of,Mevalonolactone, absolute configurationMexicanin E, structure of, 253.Microbiological transformations of ster-(+ )-Mirene, nature of, 257.Mitragynine, structure of, 291.Mitragynol, structure of, 291.Molecular-energy transfer in gases, 28.Molecular-orbital theory, semi-empirical,Molecules, adsorbed, infrared spectra of,diatomic, wave-mechanical calculationspolyatomic, wave-mechanical calcula-small, wave-mechanical calculations on,Molybdenum, colorimetric reagent for,215.184.of, 217.oids, 334.142.44.on, 25.tions on, 27.7.436.dtmn.of, 412, 425.molybdate, dtmn. of, 425.molybdenum tetraboride, 126.Dimolybdenum trisulphide, 126.Monosaccharides, 335.Monoterpenes, 248.Mycaminose, structure of, 342.Mycobacillin, amino-acid sequence in, 31 2.Mycosamine, structure of, 342.Myoglobin, whale, chain sequence in, 318.Myristic acid, analytical use of, 401.Naphthalene, 1 -chloro-4-nitro-, reactionof, with ethanolic potassium cyanide,230.2-Naphthoic acid, crystal structure of, 474.Neosamine C, structure of, 342.Nerbowdine, probable identity of, withbuphanitine, 294.Nickel, dtmn.of, 436.separation of, 407.Nickel nitrite, 130.Bisacetylacetonatonickel(II), trimeric,r - C yclopentadien yl- rr -dih y dro tetra -Diaquodisalicylaldehydatonickel(I1) ,Dinitrosylbistriphenylphosphinenickel,132.methylindenylnickel(II), 11 5.codguration of, 132.preparation of, 11 1.crystal structure of, 476.Nicotinamide, l-benzyl-1, 4-dihydro-,Nimbiol, structure of, 254.Nimbiol methyl ether, structure of, 254.Niobium, 124.Nitration, 161.Nitrogen, crystal structure of, 460.dtmn.of, in organic compounds, 430.trifhoride, reactions of, 94.Di-imide, N,H,, 95.Dinitrogen tetrafiuoride, nature of, 94.Nitric acid hemihydrate, structure of,Nitric oxide, molecular-energy transferNitrite, dtmn. of, 442.Nitrites, use of, to introduce functionalgroups, 329.Nitrosyls, 110.Nitrous oxide, molecular-energy trans-fer in, 30.94.in, 30.crystal structure of, 462.Nogiragenin, structure of, 333.Norbornadiene, 7-chloro-, reduction of,Norbornane derivatives, absolute con-ezo-Norborneol, formation of, 245.Norcamphor, photolysis of, 245.Nuclear magnetic resonance, 55.246.figurations of, 245.interpretation of spectra of, 55.use of, in organic analysis, 439.Nuclear magnetic resonance effects, inter-Nuclear spin relaxation times, 77.pretation of, 149.Obacunone, structure of, 260.Olefin complexes, 112.Olefic compounds, 215.Olefins, synthesis of, 203.Oleuropeic acid, structure of, 259.Oligosaccharides, 344.Ommatine D, 379.Ommine A, 280.Ommochromes, 378.biosynthesis of, 381.natural occurrence of, 382.Optical activity, 187.Organic chemistry, 136.theoretical, 153, 167.compounds, dtmn.of elements in, 428.structures (crystallographic), 47.Organometallic compounds, crystal struc-ture of, 464.Orixine, structure of, 288.Osmium, 129.uses of, 208.dtmn. of, 405.test for, 402.Ostreogrycin B, structure of, 311.1 ,2,4-Oxadiazole7 synthesis of, 269.Oxalyl bromide, crystal structure of, 471.1,4,2-Oxathiazoles, pyrolysis of, 270.1,3-Oxathiolan, 2-imino-, decompositionOxidation (organic), 201.Oxindoles, preparation of, 278.Oxirans, 262.Oxygen, dtmn.of, in organic compounds,of, 270.synthesis of, 262.431.molecular-energy transfer in, 29.use of, in organic oxidation, 201.Oxygen fluoride, O,F,, formation of,99526 INDEX OF 3UBJECTSPalladium, 130.Palustric acid, configuration of, 256.Parthenin, structure of, 259.Parthenolide, structure of, 251.Patchouli alcohol, structure of, 253.Penicillic acid, biogenesis of, 265.Penicillin, dtmn. of, 422.Peniocerol, structure of, 334.Pentacene, crystal structure of, 475.Peptides, 302.amino-acid sequences, in 302.cyclic, 310.synthesis of, 305.“ Perkin’s amine,” 267.Phenanthrene , 9,lO - dih y dro - 9 -me thy lene -Phenazine, N-hydroxy-, crystal structurePhenols, hydrogen bonds in, 74.Phosphorus, dtmn.of, in coal, 416.esters, kinetics of hydrolysis of, 183.pentachloride, reactions of, 98.pentafluoride, formation of, 96.trichloride, reactions of, 96, 98.trifluoride, foFmation of, 96.Compound HCP, formation of, 95.Diphosphine, tetramethyl-, reactionsPhosphates, highly condensed, test for,Phosphine oxides, uses of, 204.Phosphonitrilic fluoride, tetrameric,10-OXO-, 228.of, 476.of, 95402.crystal structure of, 462.halide polymers, 97.Phosphorane, methylenetriphenyl-, 95.Phosphoranes, use of, in synthesis ofSodium hypophosphate decahydrate, 97.Tetraethyldiphosphine disulphide, crys-olefins, 203.tal structure of, 473.Phthalates, dtmn.of, 443.Phthalocyanine, dichlorogermanium de-Phyllocladene, preparation of, 255.( f )-Pimaradiene, synthesis of, 254.Pmaric acid, structure of, 256.Pine-gum resin acids, stereochemistry of,Piperazine, dioxo-, structure of, 459.Pituitary hormones, 314.Platinum, 130.Plutonium, separation of, 405.(+)-Podocarpan-l2-one, structure of, 254.(f)-Podocarpan-l4-one, structure of, 254.Polarography, 440.Polyalthic acid, structure of, 256.Polyenes, cyclic, 232.Polyenoids, “skipped,” 219.Polymerisation of acetylenic compounds,Polyolefins, cyclic, 234.Polypyrroles, 284.Polysaccharides, 346.from bacteria, fungi, and algae, 350.Porphobilinogen, polymerisation of, 284.rivative of, 92.256.dtmn. of, 424.211.Potassium, dtmn.of, 41 1.structure of, 471.457.hydrogen di-p -ni trobenzoa te , crys t a1hydrogen maleate, crystal structure of,hydroxide, crystal structure of, 470.t-butoxide, use of, 205.Powellane, structure of, 294.Procollagen, 367.Propane, molecular-energy transfer in,Propylenediamine, optically active, 191.Protein, tobacco mosaic virus, 319.Proteins, blood, 317.structures of, 302.Pseudoaromaticity, 156.Pseudouridine, structure of, 275.Pteridine, biosynthesis of, 280.Purines, synthesis of, 279.Pyracene, crystal structure of, 474.Pyrazole, polymers of, 266.Pyrene, 4,5,9,1 O-tetrahydro-2-nitro-, for-Pyridazine, hydrogen bonding of, in aque-2,2’-Pyridil, crystal structure of, 476.Pyridines, 270.2- and 4-methanesulphonamido -,32.glyco-, 321.3-diazo-, reactions of, 266.mation of, 230.ous solution, 274.nature of, 271.272.272.2-Pyridone, 1 -methyl-, dimerisation of,2-Pyridones, aromatic character of, 64,Pyrimidines, fused, preparation of, 274.2- and 4-Pyrones, reactions of, 272.Pyrrole, 2-thiocyanato-, formation of, 264.aldehydes, synthesis of, 264.Pyrroles, 263.Pyrylium salts, formation of, 274.Quadrupole coupling, 151.Qualitative analysis, 401.inorganic, 401.organic, 402.Quantum organic chemistry, 137.basic theory of, 138.“ Queen substance,” structure of, 218.Quinodimethanes (dimethylenecyclohexa-dienes) , 225.Quinol, test for, 403.Quinolines, synthesis of, 278.o-Quinones, 3-amino-, conversion of, into“ Quinone methides ’’ (methylenecyclo-pyridinecarboxylic acids, 272.hexadienones), 228.Radialene, derivatives of, 225.Radiochemistry, 446.Rare earths, the, 121.“ Reduced rotational strength,” 189.Replacement of substituents by hydrogen,160INDEX OFResorcinol, conversion of, into 6-hexano-lactone, 206.test for, 403.Rhenium, 128.separation of, from uranium, 405.Rhodium carbonyl chloride, structure of,109.hexafluoride, 130.rr-cyclopentadienylrhodium dicarbonyl,117.Rhodommatine , 37 9.Riboflavin, synthesis of, 280.Ribonuclease, amino-acid sequence in,Ring-closure, heterocyclic, a general prin-Roseonine, structure of, 300.Rotational freedom in solution, 42.Rotundifoline, structure of, 291.Royal jelly, main acidic constituent of,217.Rubidium hydrogen di-o-nitrobenzoate,crystal structure of, 471.Rubrofusarin, structure of, 283.Ruthenium(m), test for, 402.Ruthenium hexafluoride, 128.nitrosyls, structure of, 468.319.ciple of, 284.Sabinol, oxidation of, 248.Saccharides, degradation of, 336.Saccharopine, synthesis of, 300.Saccharose, dtmn.of, 422.Salicylaldoxime, 5-chloro-, crystal struc-( -J- )-Sandarstcopimaradiene, synthesis of,Sandaracopimaric acid, identity of, withSapogenins, steroidal, 333.Sarrache, structure of, 288.Saturated molecules, theory of, 148.Saussurea lactone, structure of, 251.Scandium, 121.Scymnol sulphate, structure of, 334.Selenoalanine, p-methyl-, occurrence of,Serratamolide, structure of, 277, 312.Sex-attractant, female, of silk moth, 220.Shock tubes, use of, in study of chemicalSilicon, active, preparation of, 87.in presence of boron, 411.Silicon subchloride, SiC1, 87.tetrachloride, reactions of, 90.Dimethylsiloxane, heptamer, 88.Disilicon tri-imide, Si,(NH) 90.Disiloxane, hexamethyl-, formation of,Disilylcyanamide, 90.Octa(si1sesquioxan) derivatives, crystalstructure of, 477.Pentasilicon dodecachloride, prepara-tion of, 90.separation of, 335.ture of, 474.254.cryptopimaric acid, 256.301.reactions, 46.dtmn.of, in organic compounds, 432.89.SUBJECTS 527Silane, molecular-energy transfer in,Silicic acid, dtmn. of, 416.Silsesquioxan derivatives, crystal struc-Silyl-substituted hydrazines, 89.Tetramethylsilane, pyrolysis of, 88.Triphenylsilyltriphenylborase anion, 89.Tris-silylamines, 89.Silk moth, female sex-attractant of, 220.Silver@) carboxylates, formation of, 134.Skatole, dimer of, structure of, 277.Skytanthine, constitution of, 287.Sodium, dtmn.of, 411.31.ture of, 477.Sodium hydrogen diacetate, crystalstructure of, 471.Solanesol, structure of, 217.Solanocapsine, structure of, 297.Solasodine, partial synthesis of, 296.Solids, nuclear magnetic resonance of,Solvent effects, use of, for diagnostic pur-Solvent extraction, 403.Solvolytic reactions, general, 175.Sophorose, synthesis of, 345.Spectroscopic analysis, 432.X-ray methods in, 435.Spectroscopy, absorption, 435.76.poses, 40.atomic, 437.emission, 433.infrared, 438.turbidimetric, 437.ultraviolet and visible, 435.Starch, 348.Stereochemistry, 186.Steroid lactones, 332.Steroids, 321.of alicyclic compounds, 247.conformation of, 323.general reactions of, 323.intramolecular radical reactions of,microbiological transformations of, 334.rearrangement of the nucleus of, 329.separation of, 321.total synthesis in, 331.329.Stevane-B, 297.Steviol, stereochemistry of, 256.Stottite, crystal structure of, 470.Streptolidine, structure of, 300.Strontium, dtmn.of, 413.Strontium-90, dtmn. of, 405, 448.Structure analysis, 454.accurate, 455.Styrene monomer, dtmn. of, 443.Substitution, electrophilic, 229electrophilic aromatic, 158.homolytic, 231.homolytic aromatic, 165.nucleophilic, 230.nucleophilic aromatic, 163.Succinimide, crystal structure of, 475.N-chloro-, crystal structure of, 476.test for, 401.at a saturated carbon atom, 16752 8 INDEX 0 1Sulphur, dtmn.of, in organic compounds,in petroleum products, 422.in viscose fibres, 443.432.traces of, 437,micro-dtmn. of, 420:orthorhombic and rhombohedral, crys-Sulphur acids, kinetics of hydrolysis ofdioxide, molecular-energy transfer in,hexafluoride, molecular-energy transfertetrafluoride, as fluorinating agent, 100.trioxide, reactions of, 100.Hexasulphur imide, crystal structure of,Pentafluorosulphur peroxide, prepara-Persulphate, dtmn. of, 414.Sulphate, dtmn. of, 418, 426.Sulphides, dtmn.of, 426.small quantities of, 428.Sulphonic acids, dtmn. of, in presenceTe trasulphur t e trani tride , reaction of,with phosphorus trichloride, 96.with tertiary phosphines, 101.Tetrasulphuryl fluoride, S,O,,F,, 100.Thiosulphate, dtmn. of, in photographicgelatin, 442.tal structure of, 460.esters of, 184.31.in, 31.462.tion of, 100.pentafluoro-, formation of, 221.b- of sulphuric acid, 418.ion, use of, as precipitant, 401.ture of, 476.8-Sultones, 263.Sydnone, N-p-bromophenyl-, crystal struc-Tantalum, 124.Tazettine, acetylation of, 296.Technetium, dtmn. of, 441.dtmn. of, 413.separation of, from uranium, 405.carbonyl, preparation of, 108.hexafluoride, 127.Di-.rr-benzenetechnetium(1) cation, 11 8.Tetracyclopentadienylditechnetium,117.Telekin, structure of, 252.Teracacidin, structure of, 283.Terpenes, di-, 254.mono-, 248.sesqui-, 250.tri-, 254, 258.2,2’,2”-Terphenyl, configuration of ringsTetracene, crystal structure of, 475.Tetracyanoethylene, use of, in dtmn.ofTetramethylenedi(ammonium adipate),Tetrathiazyl fluoride, crystal structure of,Thallium, dtmn. of, 421,425.in, 64.1,3-dienes, 418.crystal structure of, 472.462.separation of, 404.SUBJECTSThermal effects (in crystallography), 459.Thermal methods of analysis, 451.1,3,4-Thiadiazoles, formation of, 270.Thiamine, biosynthesis of, 389.Thiazolid-5-one, 2-benzoylimino-Thiete 1,l-dioxide, 263.Thioethanolamine, dtmn. of, 444.Thiols, dtmn. of, 415, 422.Thiophens, 266.Thiopyrylium salts, preparation of, 275.Thorium, dtmn.of, 411, 416, 421.Thujone, isomerisation of, 248.Thujopsene, structure of, 253.Thymidine, configuration of, 275.Thymidylic acid, calcium salt, crystalThymine monohydrate, crystal structureThymol, dtmn. of, 424.Tin, dtmn. of, 407, 423.nitrate, basic, 93.1 ,4-Bistriethylstannyloxybenzene, tetra-chloro-, crystal structure of, 474.Distannane, hexamethyl-, propertiesof, 92.Distannanes, tetra-alkyldihalogeno -,nature of, 93.Stannane, di-n-butylchloro-, 92.Stannane, preparation of, 91.Stannic oxychloride, 93.“ Stannous hydroxide,” composition of,Stannyl-lithium, tri-n-butyl-, 92.3-methyl-, crystal structure of, 477.structure of, 476.of, 458.93.Tin(11) chloride dihydrate, crystal struc-Titanium, 122.ture of, 469.pptn. of, 411.dibromide, preparation of, 123.Titrimetric analysis, 413.Tobacco mosaic virus protein, 319.Totarol, hydroxy-, structure of, 256.Transition elements, the, 103.molecular hydrides of, 120.organometallic compounds of, 118.1 ,2,4-TriazolesY 269.Tricyclo-octadiene, formation of, 233.2,3,3-Trimethylbutane, 2-bromo-, crystalTrivinylbenzene, 1,2,4- and 1,3,5-, 223.Tropocollagen, 367.Tropylium, heptaphenyl-, synthesis of,Tropylium ions, 23 1.Tryptophan, biosynthesis of, 383.metabolism of, 378.Tungsten, dtmn. of, 413.tetraboride, 126.Ditungsten monoboride, 126.structure of, 472.232.Uranium, crystal structure of, 460.dtmn. of, 414, 423, 441.test for, 402.in sea water, 449.Uranium(Ir), dt,mn. of, 417529 INDEX OR' SUBJECTSUranium oxytelluride, 122.Uranyl nitrate hexahydrate, crystal struc-peroxide tetrahydrate, 122.selenides, 122.ture of, 466.Vanadium, 124.dtmn. of, 417.Bisacetylacetormto-oxovanadium, crys-Vanadium difluoride tetrahydrate, 124.Vanadium hexacarbonyl, 108.Vanadium(v), separation of, 405.Veratramine, absolute configuration of,tram-Verbenyl acetate, formation of, 250.u- and 8-Verbesinol, structure of, 252.Veticadinol, structure of, 253.Vibrational-energy transfer, theory of, 32.tal structure of, 465.297.Wafer, dtmn. of, in ethanol, 438.Wave functions, determinantal, 8.dtmn. of microgram quantities of, 437.open-shell, 17.self-consistent-field, 10.Weighing, errore in, 339, 400.Widdrol, structure of, 253.Xanthommatine, 378, 382.D-Xylothiapyranose, formation of, 343." Xylylenes " (quinodimethanes), 225.Ytterbium, dtmn. of, 423.Yttrium, 121.separation of, 404.Zapotidine, structure of, 299.Zeorin, structure of, 259.Zerewitinoff determinations, possibleZierone, structure of, 253.Zinc, 134.errors in, 209.dtmn. of, 407.Zinc chloride, crystal structure of, 450.dtmn. of, 411, 416, 421.Tetraoxalatozirconium(1v) anion, 123.Zirconium, 122.Zooanemonin, structure of, 300

ISSN:0365-6217    

DOI:10.1039/AR9615800519

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

PRINCIPAL REFERENCES USED I N CHEMICALSOCIETY PUBLICATIONSA LIST of the principal references used in this and other Chemical Societypublications was given on page 557 of last year’s issue of Annual Reports.A similar list can also be found in each January issue of Current ChemicalPapers, in the Society’s ‘‘ Handbook for Chemical Society Authors ” andin the brochure “ Presentation of Papers.”Printed in Great Britain by But.ler & Tamer Ltd, Frome and Londo

ISSN:0365-6217    

DOI:10.1039/AR9615800530

出版商:RSC    

年代:1961

数据来源: RSC